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"ALTER INDEX ... REORGANIZE" - Defragmenting Indexes in SQL Server
How To Defragment Indexes with ALTER INDEX ... REORGANIZE in SQL Server? When an index is defragmented to a small percentage, like &lt; 30%, you can use the "ALTER INDEX ... REORGANIZE" statement to defragment the index. Here is a tutorial exercise on defragmenting indexes: USE FyiCenterData; GO...
2016-11-08, 348👍, 0💬

Commit the Current Transaction in MySQL
How To Commit the Current Transaction in MySQL? If you have used some DML statements updated some data objects, and you want to have the updates to be permanently recorded in the database, you can use the COMMIT command. It will make all the database changes made in the current transaction become pe...
2016-10-17, 348👍, 0💬

Invoke the Data Pump Import Utility in Oracle
How To Invoke the Data Pump Import Utility in Oracle? The Data Pump Import utility is distributed as executable file called "impdp.exe". To invoke this utility, you should go to the "bin" directory of your Oracle server installation and run the "impdp" command. Here is tutorial exercise on how to in...
2016-10-15, 348👍, 0💬

Calculating the Difference between Two Time Values in MySQL
How To Calculate the Difference between Two Time Values in MySQL? If you have two time values, and you want to know the time difference between them, you can use the TIMEDIFF(time1, time2) function as shown below: SELECT TIMEDIFF(TIME('19:26:50'), TIME('09:26:50')) FROM DUAL; 10:00:00 SELECT TIMEDIF...
2017-12-26, 347👍, 0💬

Installing PHP on Windows in MySQL
How To Install PHP on Windows in MySQL? The best way to download and install PHP on Windows systems is to: Go to http://www.php.net, which is the official Web site for PHP. Download PHP binary version for Windows in ZIP format. Unzip the downloaded file into a directory. You are done. No need to run...
2017-07-30, 347👍, 0💬

Rebuilding All Indexes on One Table in SQL Server
How To Rebuild All Indexes on a Single Table in SQL Server? If you have several indexes on a single table and want to rebuild all of them, you may use the "ALTER INDEX ALL ON table_name REBUILD" statement as shown in the tutorial exercise below: USE FyiCenterData; GO UPDATE fyi_links_indexed SET url...
2016-11-08, 347👍, 0💬

Assigning New Column Names in a View in SQL Server
How To Assign New Column Names in a View in SQL Server? By default, column names in a view are provided by the underlying SELECT statement. But sometimes, the underlying SELECT statement can not provide names for output columns that specified as expressions with functions and operations. In this cas...
2016-11-03, 347👍, 0💬

Using ORDER BY with UNION Operators in SQL Server
How To Use ORDER BY with UNION Operators in SQL Server? If you need to sort the output from two queries grouped together with a UNION operator, you need to apply the ORDER BY clause at the group level, not at the subquery level. Note that SQL Server and MySQL react differently to the ORDER BY clause...
2016-10-26, 347👍, 0💬

"DROP LOGIN" - Deleting a Login Name in SQL Server
How To Delete a Login Name in SQL Server? If you don't want to keep a login name any more, you should delete it by using the "DROP LOGIN" statement as shown in this tutorial example: -- Login with "sa" DROP LOGIN Dba_Login; GO Command(s) completed successfully. -- View login names SELECT name, sid, ...
2016-10-19, 347👍, 0💬

Turn on Error Logs in MySQL
How To Turn on Error Logs in MySQL? If you want MySQL to write critical errors into a log file, you can use the "--log-error=fileName" option at the "mysqld" command line. The tutorial exercise below shows you a good example on how to use this option: &gt;cd \mysql\bin &gt;mkdir \mysql\logs ...
2017-11-29, 346👍, 0💬

Getting Parts of DATETIME Values as Integers in SQL Server
How To Get Parts of DATETIME Values as Integers in SQL Server Transact-SQL? Sometimes, you want to one specific part of a DATETIME value as an integer to be used in your own date and time calculations. This can be done by using the DATEPART() function in the following format: DATENAME(datepart, date...
2017-02-14, 346👍, 0💬

Attaching AdventureWorksLT Physical Files to the Server in SQL Server
How to attach AdventureWorksLT physical files to the server in SQL Server? After installed the sample database AdventureWorksLT, you need to attach it to your SQL server to make it available by follow this tutorial: EXEC sp_attach_db @dbname=N'AdventureWorksLT', @filename1=N'C:\Program Files\Microso...
2016-12-02, 346👍, 0💬

CREATE CLUSTERED INDEX - Adding Clustered Indexes in SQL Server
How To Create a Clustered Index in SQL Server? If there is no primary key in a table, you can add one clustered index to that table with CREATE CLUSTERED INDEX statement. The tutorial exercise below shows you how to create a clustered index: USE FyiCenterData; GO -- Drop the old table, if needed DRO...
2016-11-13, 346👍, 0💬

Transaction Committed when START TRANSACTION Executed in MySQL
What Happens to the Current Transaction If a START TRANSACTION Is Executed in MySQL? If you are in a middle of a current transaction, and a START TRANSACTION command is executed, the current transaction will be committed and ended. All the database changes made in the current transaction will become...
2016-10-17, 346👍, 0💬

What Is TIMESTAMP Data Type in MySQL
What Is TIMESTAMP Data Type in MySQL? A TIMESTAMP data type allows you to record a date and time like DATETIME data type. But it has some interesting features when used on a table column: The first TIMESTAMP column in a table will be assigned with the current date and time, if it is not listed in an...
2018-03-13, 345👍, 0💬

What Is a Function in Oracle
What Is a Function in Oracle? A function is a named program unit. It consists of three parts: Declaration Part - Defining the function name, calling parameters, return value type, local variables and local procedures. Declaration part is required. Execution Part - Defining execution logic with execu...
2018-01-27, 345👍, 0💬

What Is Binary Log File in MySQL
What Is Binary Log File in MySQL? MySQL server binary log file plays an important role in restoring database changes to the server. Main features on binary log files are: Binary logs can be turned on by "--log-bin=fileBaseName" option on "mysqld". Binary logs only records statements that are changin...
2017-11-29, 345👍, 0💬

What Is a Table in SQL Server
What is a table in SQL Server? A table in database is a data object used to store data. Tables have the following features: Data is stored in a table with a structure of rows and columns. Columns must be pre-defined with names, types and constrains. A table object may have other associated data obje...
2016-11-20, 345👍, 0💬

"INSTEAD OF" - Overriding DML Statements with Triggers in SQL Server
How To Override DML Statements with Triggers in SQL Server? Sometime, you may want to implement some business logics in a DML trigger to cancel the DML statement. For example, you may want to check the new email address format provided by the UPDATE statement. If the email address is invalid, you to...
2016-10-22, 345👍, 0💬

Deleting an Existing Row from a Table in MySQL
How To Delete an Existing Row from a Table in MySQL? If you want to delete an existing row from a table, you can use the DELETE statement with a WHERE clause to identify that row. Here is good sample of DELETE statements: mysql&gt; INSERT INTO fyi_links (url, id) VALUES ('www.myspace.com', 301);...
2018-01-08, 344👍, 0💬

Difference Between Clustered and Non-Clustered Indexes in SQL Server
What Is the Difference Between Clustered and Non-Clustered Indexes in SQL Server? SQL Server 2005 supports two types of indexes: clustered index and non-clustered index. Here are the main differences between them: One table can only have only one clustered index. One table can only have many non-clu...
2016-11-13, 344👍, 0💬

"CREATE LOGIN" - Creating a New Login Name in SQL Server
How To Create a New Login Name in SQL Server in SQL Server? In previous tutorials, it is assumed that you use the "sa" (System Administrator) login name to connect to your SQL Server. But that is not what a normal developer uses to connect to the server, since "sa" has the ALL permissions granted. Y...
2016-10-20, 344👍, 0💬

What Is NULL Value in MySQL
What Are NULL Values in MySQL? NULL is a special value that represents no value. Here are basic rules about NULL values: NULL presents no value. NULL is not the same as an empty string ''. NULL is not the same as a zero value 0. NULL can be used as any data type. NULL should not be used in any compa...
2018-03-28, 343👍, 0💬

Drop an Existing View in MySQL
How To Drop an Existing View in MySQL? If you have an existing view, and you don't want it anymore, you can delete it by using the "DROP VIEW viewName" statement as shown in the following script: mysql&gt; DROP VIEW faqComment; Query OK, 0 rows affected (0.00 sec) mysql&gt; SELECT * FROM faq...
2018-01-24, 343👍, 0💬

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