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Oracle SQL Tutorial 21 - How to Create / Drop Indexes
 
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In the last video, we wrote up the SQL to create three tables: CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) UNIQUE, CONSTRAINT users_pk PRIMARY KEY (user_id) ); CREATE TABLE projects( project_id NUMBER, Project_name VARCHAR2(50 CHAR) UNIQUE, creator VARCHAR2(50 CHAR) NOT NULL, CONSTRAINT projects_pk PRIMARY KEY (project_id), CONSTRAINT projects_users_fk FOREIGN KEY (creator) REFERENCES users (username) ON DELETE CASCADE ); CREATE TABLE project_users( project_id NUMBER NOT NULL REFERENCES projects (project_id) ON DELETE CASCADE, user_id NUMBER NOT NULL REFERENCES users (user_id) ON DELETE CASCADE, CONSTRAINT project_users_pk PRIMARY KEY (project_id, user_id) ); I'm going to increase the size of the users table a bit by adding a first and last name column. CREATE TABLE users( user_id NUMBER, username VARCHAR2(50 CHAR) UNIQUE, first_name VARCHAR2(50 CHAR), last_name VARCHAR2 (50 CHAR), CONSTRAINT users_pk PRIMARY KEY (user_id) ); But before we finish this design, we should consider indexing certain columns. What columns should we index? Well, as a reminder, the columns that are indexed by default are columns with the UNIQUE constraint, and those that are labeled as primary keys. Columns that are not indexed but often should be are those labeled as a foreign key. The column that jumps out the most to me is the creator column of the project table. It's the only foreign key that is not part of some index. Let's fix this by creating our first index. The way we do that is with the CREATE INDEX command. CREATE INDEX projects_creator_ix ON projects (creator) What naming convention are we following for the index? We are naming it by the table name, followed by an underscore, followed by the column, followed by an underscore, followed by an ix (for index). In this situation it does not apply, but if our foreign key column is labeled as UNIQUE, we can add the UNIQUE keyword like this: CREATE UNIQUE INDEX projects_creator_ix ON projects (creator) Now if you want to get rid of an INDEX, you can use this command: DROP INDEX projects_creator_ix Now, if we want to select data from the user table and the project table we can do that much faster. That's because the foreign key and column it references are both indexed and those are the columns we would do the join on. We will discuss how to do joins in a future video. So what are some potential problems with this database design? Overall, it is pretty good. With this design though we need to make sure there is no way for someone to update a user's username. In the next video we are going to discuss why. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Support me on Patreon! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 9840 Caleb Curry
Oracle Indexes - Beginner
 
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Oracle Indexes - Beginner
Views: 67315 Chris Ostrowski
SQL tutorial 62: Indexes In Oracle Database By Manish Sharma RebellionRider
 
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Watch and learn concepts of SQL Index In Oracle Database. In this tutorial you will learn about B-Tree Index and Function based Index. ------------------------------------------------------------------------ ►►►LINKS◄◄◄ Blog : Previous Tutorial ► ------------------------------------------------------------------------- ►►►Help Me In Getting A Job◄◄◄ ►Help Me In Getting A Good Job By Connecting With Me on My LinkedIn and Endorsing My Skills. All My Contact Info is Down Below. You Can Also Refer Me To Your Company Thanks ------------------------------------------------------------------------- Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=kb4rc1 -------------------------------------------------------------------------- ►Make sure you SUBSCRIBE and be the 1st one to see my videos! -------------------------------------------------------------------------- Amazon Wishlist: http://bit.ly/wishlist-amazon ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ►►►Find me on Social Media◄◄◄ Follow What I am up to as it happens on https://twitter.com/rebellionrider https://www.facebook.com/imthebhardwaj http://instagram.com/rebellionrider https://plus.google.com/+Rebellionrider http://in.linkedin.com/in/mannbhardwaj/ http://rebellionrider.tumblr.com/ http://www.pinterest.com/rebellionrider/ You can also Email me at for E-mail address please check About section Please please LIKE and SHARE my videos it makes me happy. Thanks for liking, commenting, sharing and watching more of our videos This is Manish from RebellionRider.com ♥ I LOVE ALL MY VIEWERS AND SUBSCRIBERS
Views: 42831 Manish Sharma
Oracle SQL Tutorial 8 - Indexes - Database Design Primer 5
 
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The concept of an index is extremely important when managing a database. An index has the power of making your database very quick or it has the power to bog down your update, delete, and insert statements. The trick is to find a good balance. You will want to index any columns that are used continually in a select or a join. By default, all primary keys are indexed as well as any columns with the UNIQUE column attribute. I suggest you consider adding an index to your foreign keys as these will often be used in joins as well. You can actually create an index on a group of columns. This will allow you to search for data and return multiple columns. This is known as a composite index. There are many other things to database design...much more than we have covered. I have decided I will cover these as we go so that we can start applying what we learn practically. Support me: http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 19498 Caleb Curry
Database Design 39 - Indexes (Clustered, Nonclustered, Composite Index)
 
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This video covers the basics of indexes. Indexing is an extremely important step of database design. Without Indexes database queries can take a substantial amount of time and hog system resources. The main two classifications of indexes are clustered and non-clustered indexes. Clustered indexes are usually the primary key and determine how the data is actually stored in the table. These are the fastest and most effective. Non-clustered indexes sort a reference to data that is still fast but doesn't actually determine how the data is structured. The best tip I can give you is to use indexes but don't over use them. Having loads of indexes on columns that are barely ever in a where clause or join can bog down the database. This is because every time the table is updated the index must also be updated! When a database looks through a table for certain where conditions on a column that does not have an index, it does an entire table scan. This is not a good practice for large databases (or even small databases but not as bad). With an index the database will do an index seek and quickly find the data you are looking for. Composite indexes consist of two or more columns within one index. Use these when you plan on using the two columns together for a database query WHERE clause. Learn more about indexes here: https://www.calebcurry.com/blogs/database-design/introduction-to-indexes Donate!: http://bit.ly/DonateCTVM2. Courses for Download: http://www.udemy.com/u/calebcurry/ (Use the coupon code "YouTubeDiscount" without the quotes) Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://Twitter.com/calebCurry Subscribe (it's free!): https://www.youtube.com/channel/UCZUyPT9DkJWmS_DzdOi7RIA?sub_confirmation=1 Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 101319 Caleb Curry
Oracle Database SQL Tutorials 29 :: How to Alter Statement  using SQL ,Add Constraint,column
 
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www.facebook.com/oracle.shohag Email : [email protected] Website : www.oraclebangla.com Topics : How to Alter Statement Object Structure using SQL ,Add Constraint,column add Oracle Database SQL Tutorials | how to Alter a table structure using SQL | Oracle Bangla 2017 How to alter a Table Structure using SQL | Alter statement | SQL tutorials | Oracle Bangla 2017 | HD Oracle SQL Tutorials. how to alter a table using sql
Views: 1263 Oracle Bangla
Database Tutorial - 18 - Creating Index
 
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Please Rate, Comment and Subscribe. Available for Hire: http://www.naveedziarab.com Twitter: https://twitter.com/CreativityTuts Website: http://www.creativitytuts.org
Views: 12824 Naveed Ziarab
mysql tutorial for beginners (6/8) : Indexes
 
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mysql tutorial for beginners (6/8) : Indexes As things stand, the table students works and can be searched without problem by MySQL—until it grows to more than a couple of hundred rows, At that point, database accesses will get slower and slower with every new row added, because MySQL has to search through every row whenever a query is issued. This is like searching through every book in a library whenever you need to look something up. Of course, you don’t have to search libraries that way, because they have either a card index system or, most likely, a database of their own. The way to achieve fast searches is to add an index, either when creating a table or at any time afterward. But the decision is not so simple. For example, there are different index types such as a regular INDEX, PRIMARY KEY, and FULLTEXT. Also, you must decide which columns require an index, a judgment that requires you to predict whether you will be searching any of the data in that column. And even when you’ve decided that, you still have the option of reducing index size by limiting the amount of each column to be indexed. If we imagine the searches that may be made on the students table, it becomes apparent that all of the columns may need to be searched. Anyway, go ahead and add an index to each of the columns, using the commands: ALTER TABLE students ADD INDEX(name(3)); An alternative to using ALTER TABLE to add an index is to use the CREATE INDEX command. They are equivalent, except that CREATE INDEX cannot be used for creating a PRIMARY KEY CREATE INDEX surname ON students (surname(5)); DESCRIBE students; These commands create indexes on both the name and surname columns, limiting name index to only the first 3 characters, and surname index to the first 5 characters. For instance, when MySQL indexes the following name: SAFAA It will actually store in the index only the first 3 characters: SAF This is done to minimize the size of the index, and to optimize database access speed. DESCRIBE command shows the key MUL for each column. This key means that multiple occurrences of a value may occur within that column, which is exactly what we want, as name or surname may appear many times. You don’t have to wait, until after creating a table to add indexes. In fact, doing so can be time-consuming, as adding an index to a large table can take a very long time. Therefore, let’s look at a command that creates the table students with indexes already in place. CREATE TABLE students ( Id_studnet SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, name VARCHAR(10) NOT NULL, surname VARCHAR(20) NOT NULL, email VARCHAR(30) NOT NULL, INDEX(name(3)), INDEX(surname(5)), ,PRIMARY KEY(id_studnet),UNIQUE(email)); Another important index, PK, its single unique key for each student to enable instant accessing of a row. The importance of having a key with a unique value for each row will come up when we start to combine data from different tables. You can add PK, while you create the table at the first time, or later by issuing the following command: ALTER TABLE students ADD PRIMARY KEY(id_student); The last important index, FULLTEXT index Unlike a regular index, MySQL’s FULLTEXT allows super-fast searches of entire columns of text. It stores every word in every data string in a special index that you can search using “natural language,” in a similar manner to using a search engine. It’s not strictly true that MySQL stores all the words in a FULLTEXT index, because it has a built-in list of more than 500 words that it chooses to ignore because they are so common that they aren’t very helpful for searching anyway. This list, called stopwords, includes the, as, is, of, and so on. The list helps MySQL run much more quickly when performing a FULLTEXT search and keeps database sizes down. FULLTEXT indexes can be created for CHAR, VARCHAR, and TEXT columns only. A FULLTEXT index definition can be given in the CREATE TABLE statement when a table is created, or added later using ALTER TABLE (or CREATE INDEX). Adding a FULLTEXT index to the table students for the columns name and surname ALTER TABLE classics ADD FULLTEXT(name,surname); this index is in addition to the ones already created and does not affect them You can now perform FULLTEXT searches across this pair of columns. If you find that MySQL is running slower than you think it should be when accessing your database, the problem is usually related to your indexes. Either you don’t have an index where you need one, or the indexes are not optimally designed. Tweaking a table’s indexes will often solve such a problem. In the next tutorial, we will learn about, using FOREIGN KEY Constraints and how to join tables together. Subscribe for more: ---------------------------------------------------------------------------- https://www.youtube.com/subscription_center?add_user=saf3al2a SWE.Safaa Al-Hayali - saf3al2a
Views: 30390 Safaa Al-Hayali
SQL with Oracle 10g XE - Using ALTER TABLE to Modify Table Columns
 
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In this video I use the ALTER TABLE command to modify an existing field column. The command will allow you to change the data types, whether the field can be null, or even the primary key. When using the ALTER TABLE command you would use the keyword MODIFY to make changes to an existing column. Be careful when changing a data type of the null field as existing data may cause an error if not in compliance with the new change. The code I used to alter the Books table is : ALTER TABLE BOOKS MODIFY ISBN_10 VARCHAR(13); This video is part of a series of videos with the purpose of learning the SQL language. For more information visit Lecture Snippets at http://lecturesnippets.com.
Views: 16301 Lecture Snippets
Oracle Database | Bangla tutorials 26 ::  Database Object | Create index
 
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www.facebook.com/oracle.shohag Email : [email protected] Website : www.oraclebangla.com Topics :Database Object Create index
Views: 1149 Oracle Bangla
Indexes in sql server   Part 35
 
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In this video we will learn about What are indexes Why do we use indexes Advantages of indexes These concepts are applicable to sql server 2000, 2005 and 2008 Text version of the video http://csharp-video-tutorials.blogspot.com/2012/09/indexes-in-sql-server-part-35.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-35-indexes.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 407463 kudvenkat
Oracle Heap Tables or SQL Server Clustered Indexes
 
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Live discussion between Jonathan Lewis and Grant Fritchey. Thurs 7th June 2012 Oracle and SQL Server may both share a common language, but certain things are handled quite differently. Jonathan Lewis (OakTable Network, Oracle Ace Director) is used to seeing heap tables (almost) everywhere, but Grant Fritchey (Microsoft SQL Server MVP) is used to seeing clustered indexes (almost) everywhere. But which arrangement performs better? And is comparative performance even the right thing to measure? In this live discussion, these two heavyweights in their respective technology areas will debate the pros and cons of Oracle Heap Tables and SQL Clustered Indexes. Jonathan and Grant may even play a few unexpected cards during the discussion. Be prepared for a lively exchange which will not only entertain, but will teach you key concepts on Oracle and SQL Server. For our complete archive, and to sign up for upcoming webinars please go to http://www.red-gate.com/oracle-webinars
Views: 879 Redgate Videos
Oracle SQL Tutorial   Adding a column to a table   YouTube
 
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Oracle SQL Tutorial Adding a column to a table how to add column in your oracle table is shown in above tutorial
Views: 189 magan lal
SQL Server training and interview question:-What is index and how does it make your search faster ?.
 
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For more such videos visit http://www.questpond.com For more such videos subscribe https://www.youtube.com/questpondvideos?sub_confirmation=1 See our other Step by Step video series below :- Learn Data Science in 1 hour :- https://tinyurl.com/y5o7qbau Learn angular tutorial step by step https://tinyurl.com/ycd9j895 Learn C# Step by Step https://goo.gl/FNlqn3 Learn Design Pattern Step by Step https://goo.gl/eJdn0m Learn Azure Step by Step :- https://tinyurl.com/y6fmrech Learn SQL Server Step by Step http://tinyurl.com/ja4zmwu Learn Data structures & algorithm https://tinyurl.com/ybx29c5s Learn MVC Core step by step :- http://tinyurl.com/y9jt3wkv Learn MSBI Step by Step in 32 hours:- https://goo.gl/TTpFZN Learn Xamarin Mobile Programming Step by Step :- https://goo.gl/WDVFuy Learn SharePoint Step by Step in 8 hours:- https://goo.gl/XQKHeP Learn Tableau step by step :- https://tinyurl.com/kh6ojyo Preparing for C# / .NET interviews start here http://www.youtube.com/watch?v=gaDn-sVLj8Q In this SQL Server training video we will understand what are indexes and how they make your search faster. We also run through the fundamentals of B-tree or balanced tree structure. Its also one of those favourite SQL Server interview questions which is asked in SQL Server interviews. We are also distributing a 100 page Ebook "Sql Server Interview Question and Answers". If you want this ebook please share this video in your facebook/twitter/linkedin account and email us on [email protected] with the shared link and we will email you the PDF.
Views: 246394 Questpond
SQL script to insert into many to many table
 
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Text Article http://csharp-video-tutorials.blogspot.com/2017/02/sql-script-to-insert-into-many-to-many.html Slides http://csharp-video-tutorials.blogspot.com/2017/02/sql-script-to-insert-into-many-to-many_6.html SQL Server Interview Questions and Answers text articles & slides http://csharp-video-tutorials.blogspot.com/2014/05/sql-server-interview-questions-and.html SQL Server Interview Questions and Answers playlist https://www.youtube.com/playlist?list=PL6n9fhu94yhXcztdLO7i6mdyaegC8CJwR All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this video we will discuss how to insert data into a table that has many-to-many relationship Create table Students ( Id int primary key identity, StudentName nvarchar(50) ) Go Create table Courses ( Id int primary key identity, CourseName nvarchar(50) ) Go Create table StudentCourses ( StudentId int not null foreign key references Students(Id), CourseId int not null foreign key references Courses(Id) ) Go Students - Id column is identity column Courses - Id column is identity column StudentCourses - StudentId and CourseId columns are foreign keys referencing Id column in Students and Courses tables As you can see, StudentCourses is a bridge table that has many to many relationship with Students and Courses tables. This means a given student can be enrolled into many courses and a given course can have many students enrolled. Below is the question asked in an interview for SQL Server Developer role. Write a SQL script to insert data into StudentCourses table. Here are the rules that your script should follow. 1. There will be 2 inputs for the script Student Name - The name of the student who wants to enroll into a course Course Name - The name of the course the student wants to enroll into 2. If the student is already in the Students table, then use that existing Student Id. If the student is not already in the Students table, then a row for that student must be inserted into the Students table, and use that new student id. 3. Along the same lines, if the course is already in the Courses table, then use that existing Course Id. If the course is not already in the Courses table, then a row for that course must be inserted into the Courses table, and use that new course id. 4. There should be no duplicate student course enrollments, i.e a given student must not be enrolled in the same course twice. For example, Tom must not be enrolled in C# course twice. Answer : To avoid duplicate student course enrollments create a composite primary key on StudentId and CourseId columns in StudentCourses table. With this composite primary key in place, if someone tries to enroll the same student in the same course again we get violation of primary key constraint error. Alter table StudentCourses Add Constraint PK_StudentCourses Primary Key Clustered (CourseId, StudentId) Here is the SQL script that inserts data into the 3 tables as expected Declare @StudentName nvarchar(50) = 'Sam' Declare @CourseName nvarchar(50) = 'SQL Server' Declare @StudentId int Declare @CourseId int -- If the student already exists, use the existing student ID Select @StudentId = Id from Students where StudentName = @StudentName -- If the course already exists, use the existing course ID Select @CourseId = Id from Courses where CourseName = @CourseName -- If the student does not exist in the Students table If (@StudentId is null) Begin -- Insert the student Insert into Students values(@StudentName) -- Get the Id of the student Select @StudentId = SCOPE_IDENTITY() End -- If the course does not exist in the Courses table If (@CourseId is null) Begin -- Insert the course Insert into Courses values(@CourseName) -- Get the Id of the course Select @CourseId = SCOPE_IDENTITY() End -- Insert StudentId & CourseId in StudentCourses table Insert into StudentCourses values(@StudentId, @CourseId) If required, we can very easily convert this into a stored procedure as shown below. Create procedure spInsertIntoStudentCourses @StudentName nvarchar(50), @CourseName nvarchar(50) as Begin Declare @StudentId int Declare @CourseId int Select @StudentId = Id from Students where StudentName = @StudentName Select @CourseId = Id from Courses where CourseName = @CourseName If (@StudentId is null) Begin Insert into Students values(@StudentName) Select @StudentId = SCOPE_IDENTITY() End If (@CourseId is null) Begin Insert into Courses values(@CourseName) Select @CourseId = SCOPE_IDENTITY() End Insert into StudentCourses values(@StudentId, @CourseId) End Use the following statement to execute the stored procedure Execute spInsertIntoStudentCourses 'Tom','C#'
Views: 94049 kudvenkat
11 SQL with Oracle 10g XE   Using ALTER TABLE to ADD and DROP Table Columns
 
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11 SQL with Oracle 10g XE Using ALTER TABLE to ADD and DROP Table Columns
Views: 31 Cambo Movies
Clustered and nonclustered indexes in sql server   Part 36
 
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In this video we will learn about 1. Different types of indexes in sql server 2. What are clustered indexes 3. What are NonClustered indexes 4. Difference between clustered and non clustered indexes Text version of the video http://csharp-video-tutorials.blogspot.co.uk/2012/09/clustered-and-non-clustered-indexes.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-36-clustered-nonclustered-indexes.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 494265 kudvenkat
B-Tree Indexes
 
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In this video, I'd like to take a look at B-tree indexes and show how knowing them can help design better database tables and queries.
Advantages and disadvantages of indexes in sql server   Part 38
 
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In this video we will learn about 1. Advantages and disadvantages of indexes 2. The types of queries that can benefit from indexes 3. Covering Queries Text version of the video http://csharp-video-tutorials.blogspot.com/2012/09/advantages-and-disadvantages-of-indexes.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-38-adv-dis-adv-of-indexes.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 167873 kudvenkat
Heap Tables and Index Organized Tables in Oracle | Chris Saxon
 
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Chris Saxon, a database evangelist, developer advocate, and SQL specialist with Oracle, uses up his two minutes with a tip on using heap tables and index organized tables in Oracle Database.
Views: 2842 ArchBeat Archive
Oracle SQL Tutorial 11 - CREATE TABLE
 
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The way you create a table is to use the CREATE TABLE command. CREATE TABLE users() So in this situation, the name comes right after the TABLE keyword. The next thing we do is put all of the columns on a line that we want to put in our table. CREATE TABLE users( user_id, username, first_name, last_name ) Notice the naming conventions here. For this series we are going to make columns with what is known as snake casing. This is where each individual word is separated by an underscore. if you have more than one column, all of them have to have commas except the last one. The comma is a way to say that another column is coming, so you don't need to do it on the last one. Now you would think we were done, but we also have to say what data type each column is. Later we will extensively discuss data types so we can focus on them exclusively. For now, here are the data types we are going to use: CREATE TABLE users( user_id NUMBER, username VARCHAR2(50), first_name VARCHAR2(50), last_name VARCHAR2(50) ) Now, inside of the parenthesis for varchar2, we pass in a number... This is the max length of the string. But the question is, what is it measured in? The default is actually in bytes, not characters. For example if we have the string hello, it is 5 characters, but it might take up a total of 10 bytes of storage. So I would recommend adding the keyword char right after the number so it defaults to 50 characters, not bytes. CREATE TABLE users( user_id NUMBER, username VARCHAR(50 CHAR), first_name VARCHAR2(50 CHAR), last_name VARCHAR2(50 CHAR) ) This will work to create a table, but it's really missing a lot of information… which column is the primary key? Are we adding any indexes? Is there any thing else we need to say about these columns? So as you can tell, we are making progress, but there is still so much to learn. The biggest gotcha to remember from this video is that the data type VARCHAR ends in a 2, stupid, right? who would end the name of something with a 2? Once again, this is Caleb from CalebTheVideoMaker2, and we will catch you in the next one! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ HELP ME! http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 39093 Caleb Curry
Oracle SQL PLSQL 12C Tutorial 15 - ALTER Statement
 
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This Video Tutorial Will Describe how to change the structure of an existing table. This command will also work on other versions of database like Oracle 11g Database, Oracle 10g Database, Oracle 9i Database, Oracle 8i Database, Oracle 8 Database and so on. This command is used to add, modify or delete the columns from the table. You can add, modify or delete a single column or multiple columns at a time. Full Syntax will be given in this video tutorial about how to use the ALTER table command. Along with the live example to add, modify or delete the columns from the table. All the keywords, format, mandatory clauses etc are described in this video.
Which Order Should Columns Go in an Index?: Finding All the Red Sweets Part 4
 
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When you create an index on multiple columns there's an important question you need to answer: In which order should you list the columns? This video looks at some of the factors you should consider to help answer this question. ============================ The Magic of SQL with Chris Saxon Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Views: 4515 The Magic of SQL
Oracle SQL Tutorial 9 - Intro to Queries
 
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This video is for beginners who have never worked with SQL Developer, and we are going to teach how to begin writing queries. So the queries we are going to start with are queries when we give the database an expression and it will return back some kind of value. The most common keyword you are going to need to know for Oracle is SELECT. SELECT is the command we use to get data from the database. Even though we have not really put any data in our database, we can still use the SELECT statement to get data. That's because the database is capable of doing more than just creating tables and retrieving data from tables. So our first goal is to essentially write a Hello World, which just displays the text hello world to us. A good place to start is with: SELECT 'Hello World' This would actually work for many database management systems, but when you run it you will get an error. This actually doesn't work with Oracle, it will tell us we always need the FROM keyword. To get around this, there is a magical table called DUAL. We can put anything we want to SELECT and then say FROM DUAL and it will work. SELECT 'Hello World' FROM DUAL We can also do math: SELECT 1+1 FROM DUAL And we can run even run functions: SELECT SYSTIMESTAMP FROM DUAL To put all of this together, you can grab all of this data at the same time using commas to separate different columns from our generated table: SELECT 'Hello World', 1+1, SYSTIMESTAMP FROM DUAL Support me on Patreon: http://www.patreon.com/calebcurry Subscribe to my newsletter: http://bit.ly/JoinCCNewsletter Donate!: http://bit.ly/DonateCTVM2. ~~~~~~~~~~~~~~~Additional Links~~~~~~~~~~~~~~~ More content: http://CalebCurry.com Facebook: http://www.facebook.com/CalebTheVideoMaker Google+: https://plus.google.com/+CalebTheVideoMaker2 Twitter: http://twitter.com/calebCurry Amazing Web Hosting - http://bit.ly/ccbluehost (The best web hosting for a cheap price!)
Views: 31659 Caleb Curry
7. Create Table in SQL (Hindi)
 
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Please Subscribe Channel Like, Share and Comment Visit : www.geekyshows.com
Views: 136452 Geeky Shows
SQL Tutorial - 13: Inserting Data Into a Table From Another Table
 
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In this tutorial we'll learn to use the INSERT Query to copy data from one table into another.
Views: 265269 The Bad Tutorials
SelectTec | Aula Nº 28 | Create Index - Oracle SQL Developer
 
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create index syntax: create unique index nome_indice tabela(colula)
Views: 1710 SelectTec
Get Fuzzy with APEX and Oracle Text
 
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Ever had a requirement to add fuzzy search to your APEX application ...? And did you know that Oracle Database and APEX provide everything you need? This Application Express Office Hours session shows how to provide error-tolerant searching to your end users using Application Express and the Oracle TEXT database feature. Oracle TEXT allows to build just one Index for all your data and it provides linguistic and fuzzy search capabilities. The APEX Interactive Grid component allows to declaratively integrate such an index - however, other APEX components can leverage Oracle TEXT as well. The session shows how to build the Oracle Text index and how to use it with various APEX components. Tips and Tricks for practical usage will wrap the session up. Slides: https://www.slideshare.net/CarstenCzarski/find-anything-in-your-apex-app-fuzzy-search-with-oracle-text Chat: http://bit.ly/apex_office_hours_chat__20190124 Video Highlights: [2:50] Introduction [8:30] Oracle Text [11:25] APEX Interactive Grid Demo [15:10] Oracle Text Fundamentals [24:00] Demo - Building a new Text Index [42:40] Summary [44:30] Questions and Answers https://apex.oracle.com
Views: 963 Oracle Developers
Oracle Database11g tutorials 8 || SQL DISTINCT with multiple columns |SQL Distinct with Two columns
 
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This SQL tutorial and Oracle database 11g tutorial for beginners will show how to use SQL DISTINCT keyword with SQL Select clause. This Video is in the continuation of previous video on SQL distinct with one column. In this video we will see How to use SQL distinct with multiple columns and SQL distinct with two columns Tool used in this tutorial is SQL developer. This tutorial series is part of SQL expert exam certification training. If you are preparing for SQL certification you can use my tutorials. This SQL Tutorial is a part of free training. Copy Cloud referral link || Use this link to join copy cloud and get 20GB of free storage https://copy.com?r=j7eYO7 Contacts Email [email protected] Twitter https://twitter.com/rebellionrider Instagram http://instagram.com/rebellionrider Facebook. https://www.facebook.com/imthebhardwaj Linkedin. in.linkedin.com/in/mannbhardwaj/ Thanks for linking, commenting, sharing and watching more of our videos This is Manish From The Code makers
Views: 101829 Manish Sharma
Indexed views in sql server   Part 41
 
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In this video we will learn about, creating indexed views. A unique clustered index, is the first index that should be created on a view. Indexed views are also called as materialized views Text version of the video http://csharp-video-tutorials.blogspot.com/2012/09/indexed-views-in-sql-server-part-41.html Slides http://csharp-video-tutorials.blogspot.com/2013/09/part-41-indexed-views.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 161610 kudvenkat
PRIMARY KEY and UNIQUE KEY Constraints in Oracle Database
 
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unique constraint oracle oracle check constraint alter table add constraint primary key oracle oracle unique constraint multiple columns oracle unique constraint vs unique index
Views: 13 Adam Tech
JSON in Oracle 12C Part 1 - Creating JSON Columns in Tables
 
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This is the first video in a series of videos on how to handle JSON data in Oracle 12C. In this video, I'll show you how to create columns in a table that will be used to hold JSON data.
Views: 5343 Pretty Printed
Part 6   Transform rows into columns in sql server
 
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Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2014/06/part-6-transform-rows-into-columns-in.html This is another common sql server interview question. We will be using Countries table in this example. SQL to create the table Create Table Countries ( Country nvarchar(50), City nvarchar(50) ) GO Insert into Countries values ('USA','New York') Insert into Countries values ('USA','Houston') Insert into Countries values ('USA','Dallas') Insert into Countries values ('India','Hyderabad') Insert into Countries values ('India','Bangalore') Insert into Countries values ('India','New Delhi') Insert into Countries values ('UK','London') Insert into Countries values ('UK','Birmingham') Insert into Countries values ('UK','Manchester') Here is the interview question. Write a sql query to transpose rows to columns. Using PIVOT operator we can very easily transform rows to columns. Select Country, City1, City2, City3 From ( Select Country, City, 'City'+ cast(row_number() over(partition by Country order by Country) as varchar(10)) ColumnSequence from Countries ) Temp pivot ( max(City) for ColumnSequence in (City1, City2, City3) ) Piv
Views: 204586 kudvenkat
03 - Curso de Oracle 10g - Alter Table Add
 
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Curso Oracle SQL Essentials http://bit.ly/1N3upVn Curso Oracle SQL Expert - Certificação 1Z0-047 http://bit.ly/1G4rKWG Curso Oracle Aprendendo SQL - Preparatório exames 1Z0-051/1Z0-061 http://bit.ly/1eqDlsr Neste Curso de Oracle 10g será demonstrado todo passo a passo desde a istalação até administração e programação em PLSql. No Curso de Oracle 10g você será direcionado passo a passo durante o aprendizado com ótima qualidade do conteúdo disponibilizado. Este curso é oferecido gratuitamente aqui porém caso tenha interesse em se aprofundar e aprender o oracle a fundo praparando para certificação acesse os links acima. Tags: oracle cursos gratuitos curso de oracle banco de dados
Views: 4871 Cursos Interativos
Part 12   Can we join two tables without primary foreign key relation
 
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Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2014/09/part-12-can-we-join-two-tables-without.html Can we join two tables without primary foreign key relation Yes, we can join two tables without primary foreign key relation as long as the column values involved in the join can be converted to one type. ID column in Departments table is not the primary Key and DepartmentId column in Employees table is not the foreign key. But we can still join these tables using ID column from Departments table and DepartmentId column from Employees table, as both the columns involved in the join have same data type i.e int. Select Employees.Name as EmployeeName, Departments.Name as DepartmentName from Employees join Departments on Departments.ID = Employees.DepartmentId The obious next question is, if primary foreign key relation is not mandatory for 2 tables to be joined then what is the use of these keys? Primary key enforces uniqueness of values over one or more columns. Since ID is not a primary key in Departments table, 2 or more departments may end up having same ID value, which makes it impossible to distinguish between them based on the ID column value. Foreign key enforces referential integrity. Without foreign key constraint on DepartmentId column in Employees table, it is possible to insert a row into Employees table with a value for DepartmentId column that does not exist in Departments table. The following insert statement, successfully inserts a new Employee into Employees table whose DepartmentId is 100. But we don't have a department with ID = 100 in Departments table. This means this employee row is an orphan row, and the referential integrity is lost as result Insert into Employees values (8, 'Mary', 'Female', 80000, 100) If we have had a foreign key constraint on DepartmentId column in Employees table, the following insert statement would have failed with the following error. Msg 547, Level 16, State 0, Line 1 The INSERT statement conflicted with the FOREIGN KEY constraint. The conflict occurred in database "Sample", table "dbo.Departments", column 'ID'.
Views: 123673 kudvenkat
Adding a check constraint - Part 6
 
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In this video we will learn 1. How to add a check constraint in SQL Server 2. The purpose or use of check constraint Text version of the video http://csharp-video-tutorials.blogspot.co.uk/2012/08/check-constraint-in-sql-server-part-6.html Slides http://csharp-video-tutorials.blogspot.com/2013/08/part-6-check-constraint.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists
Views: 407695 kudvenkat
Create Index Script
 
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Views: 135 Jonah Coleman
Oracle Database 12c: Partitioning Improvements with Tom Kyte
 
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Tom Kyte introduces the new partitioning improvements in Oracle Database 12c, followed by a demo of global index maintenance. For more information: "Asynchronous Global Index Maintenance for Dropping and Truncating Partitions" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=VLDBG14107 "Changes for Very Large Databases and Partitioning in Oracle Database 12c Release 1" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=VLDBG14100 "ALTER INDEX COALESCE Clause" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=SQLRF52782 "DBMS_PART.CLEANUP_GIDX Procedure" http://www.oracle.com/pls/topic/lookup?ctx=db121&id=ARPLS74409
Views: 13971 OracleDBVision
How Many Indexes Are Too Many?: Finding All The Red Sweets Part 5
 
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Every index you add to a table increases its storage requirements and DML overheads. So it's a good idea to create as few as possible. When you have two or more indexes using the same columns, you may be able to get away with just one. But how do you decide which to keep? This video discusses how to analyze your queries so you can cut the number of indexes you create. ============================ The Magic of SQL with Chris Saxon Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Views: 2427 The Magic of SQL
Foreign Key | Database Management System
 
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To ask your doubts on this topic and much more, click on this Direct Link: http://www.techtud.com/video-lecture/lecture-foreign-key IMPORTANT LINKS: 1) Official Website: http://www.techtud.com/ 2) Virtual GATE: http://virtualgate.in/login/index.php Both of the above mentioned platforms are COMPLETELY FREE, so feel free to Explore, Learn, Practice & Share! Our Social Media Links: Facebook Page: https://www.facebook.com/techtuduniversity Facebook Group: https://www.facebook.com/groups/virtualgate Google+ Page: https://plus.google.com/+techtud/posts Last but not the least, SUBSCRIBE our YouTube channel to stay updated about the regularly uploaded new videos.
Views: 277988 Techtud
Part 1   How to find nth highest salary in sql
 
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Link for all dot net and sql server video tutorial playlists http://www.youtube.com/user/kudvenkat/playlists Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2014/05/part-1-how-to-find-nth-highest-salary_17.html This is a very common SQL Server Interview Question. There are several ways of finding the nth highest salary. By the end of this video, we will be able to answer all the following questions as well. How to find nth highest salary in SQL Server using a Sub-Query How to find nth highest salary in SQL Server using a CTE How to find the 2nd, 3rd or 15th highest salary Let's use the following Employees table for this demo Use the following script to create Employees table Create table Employees ( ID int primary key identity, FirstName nvarchar(50), LastName nvarchar(50), Gender nvarchar(50), Salary int ) GO Insert into Employees values ('Ben', 'Hoskins', 'Male', 70000) Insert into Employees values ('Mark', 'Hastings', 'Male', 60000) Insert into Employees values ('Steve', 'Pound', 'Male', 45000) Insert into Employees values ('Ben', 'Hoskins', 'Male', 70000) Insert into Employees values ('Philip', 'Hastings', 'Male', 45000) Insert into Employees values ('Mary', 'Lambeth', 'Female', 30000) Insert into Employees values ('Valarie', 'Vikings', 'Female', 35000) Insert into Employees values ('John', 'Stanmore', 'Male', 80000) GO To find the highest salary it is straight forward. We can simply use the Max() function as shown below. Select Max(Salary) from Employees To get the second highest salary use a sub query along with Max() function as shown below. Select Max(Salary) from Employees where Salary [ (Select Max(Salary) from Employees) To find nth highest salary using Sub-Query SELECT TOP 1 SALARY FROM ( SELECT DISTINCT TOP N SALARY FROM EMPLOYEES ORDER BY SALARY DESC ) RESULT ORDER BY SALARY To find nth highest salary using CTE WITH RESULT AS ( SELECT SALARY, DENSE_RANK() OVER (ORDER BY SALARY DESC) AS DENSERANK FROM EMPLOYEES ) SELECT TOP 1 SALARY FROM RESULT WHERE DENSERANK = N To find 2nd highest salary we can use any of the above queries. Simple replace N with 2. Similarly, to find 3rd highest salary, simple replace N with 3. Please Note: On many of the websites, you may have seen that, the following query can be used to get the nth highest salary. The below query will only work if there are no duplicates. WITH RESULT AS ( SELECT SALARY, ROW_NUMBER() OVER (ORDER BY SALARY DESC) AS ROWNUMBER FROM EMPLOYEES ) SELECT SALARY FROM RESULT WHERE ROWNUMBER = 3
Views: 975595 kudvenkat
How to Convert a Non-Partitioned Table to Partitioned using Oracle Database 12c R2
 
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Oracle Database 12c Release 2 New Feature! Learn how to convert a non-partitioned table to a partitioned table - Online! This new method - using ALTER TABLE MODIFY - is much simpler than DBMS_REDEFINITION. In this free tutorial from SkillBuilders and Oracle Certified Master DBA John Watson you'll see a demonstration of converting the table and the impact on the underlying table and indexes. See all our free Oracle Database Tutorials at http://www.skillbuilders.com/free-oracle-tutorials.
Views: 3595 SkillBuilders
RENAME COLUMN, DROP COLUMN in Oracle SQL
 
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Oracle SQL tutorials, How to RENAME COLUMN, DROP COLUMN
06 - Curso de Oracle 10g - Group by Index
 
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Curso Oracle SQL Essentials http://bit.ly/1N3upVn Curso Oracle SQL Expert - Certificação 1Z0-047 http://bit.ly/1G4rKWG Curso Oracle Aprendendo SQL - Preparatório exames 1Z0-051/1Z0-061 http://bit.ly/1eqDlsr Neste Curso de Oracle 10g será demonstrado todo passo a passo desde a istalação até administração e programação em PLSql. No Curso de Oracle 10g você será direcionado passo a passo durante o aprendizado com ótima qualidade do conteúdo disponibilizado. Este curso é oferecido gratuitamente aqui porém caso tenha interesse em se aprofundar e aprender o oracle a fundo praparando para certificação acesse os links acima. https://youtu.be/w0RupOMvX70 Tags: oracle cursos gratuitos curso de oracle banco de dados
Views: 2490 Cursos Interativos
The Magic of SQL: Column Update Mystery
 
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You use the update statement in SQL to modify existing values in a row. Normally you have to assign values to each column explicitly. In this video Chris updates the value in one column and also changes the value in another column - without any triggers in sight! Watch the video to see how it's done! ============================ The Magic of SQL with Chris Saxon Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Views: 6568 The Magic of SQL
Excel Magic Trick 1349: Power Query with Input Variables from Excel Sheet to Extract Records
 
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Download File: http://people.highline.edu/mgirvin/excelisfun.htm See how to use Power Query (Get & Transform) with Input Variables from Excel Sheet to Extract Records and create a Revenue Report. Here are the steps: 1. (00:15) Introduction including Preview of Finished Solution and Preview of steps necessary to accomplish this goal. 2. (02:00) Import and transform Data Set, including removing Columns, Filter For Records and adding an extra Column to calculate Net Revenue using the Number.Round Power Query Function. 3. (06:38) Load Report to Sheet 4. (07:09) Import each Parameter/Criteria Table. 5. (07:36) Convert each Criteria Table to a single Text Item using the Record.Field Power Query Function. 6. (11:38) Declare and Insert Variables into M Code for Report 7. (14:10) Test Reporting System 8. (14:30) Create Recorded Macro To Refresh All and assign it to a Form button 9. (16:40) Test Macro and Reporting System 10. (17:25) Summary
Views: 84176 ExcelIsFun
Asp.Net Gridview :  Bind Database Table
 
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How to Bind Database Table in Asp.Net Gridview In this video, we have discussed how to bind or display database table in asp.net gridview Using SQL Server.as a last column we have added link button to select a specific row. Best Asp.Net Book from Amazon (Affiliate) : ➤ http://geni.us/hV1bX1m Download Project From : ➤ https://goo.gl/z4nwbc Buy me a Coffee (Channel Support By Donation) ➤ https://goo.gl/bPcyXW Subscribe to this channel ➤ https://goo.gl/RFY5C2 Link to this video ➤ https://youtu.be/_Ms5_6e7Fu4 Our Website ➤ http://www.codaffection.com ______________ ✪ Related Links ________________ ✪ Asp.Net - Insert Update Delete : https://goo.gl/oxDoDK ✪ Asp.Net Login Page : https://goo.gl/sdqHqu ✪ Complete Asp.net Tutorial : https://goo.gl/qshuJk ______________ ⌘ Social Media Links ________________ Blog : http://www.codaffection.com Facebook : https://www.facebook.com/codaffection Google plus : https://plus.google.com/+codaffection Twitter : https://twitter.com/codaffection Youtube : https://youtube.com/codaffection ______________ ↪ About this Channel ________________ CodAffection - for passionate programmers. This channel is all about teaching and inspiring developers to build applications/ websites in various technologies like Angular, NodeJS, Asp.Net MVC, JavaScript, SQL, React, Python etc. 2 Videos per Week - 12:30 PM UTC On MON and THU ______________ ₪ All Playlist ________________ https://goo.gl/gvjUJ7 : Asp.Net MVC https://goo.gl/ahk39S : Angular 5 https://goo.gl/viJcFs : Node JS https://goo.gl/itVayJ : Web API https://goo.gl/YJPPAH : MEAN Stack https://goo.gl/s1zJxo : C# Tutorial https://goo.gl/GXC2aJ : Asp.Net WebForm https://goo.gl/vHS9Hd : C# WinForm https://goo.gl/MLYS9e : MS SQL https://goo.gl/Ha71kq : Angular 4 https://goo.gl/5Vou7t : Crystal Report https://goo.gl/EPZ69B : Common C# Excercises https://goo.gl/qEWJCs : CG Exercises in C Program
Views: 60543 CodAffection

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