When you create a computed column in SQL Server, you have the option of flagging it as “persisted”. A persisted computed column is one that is physically stored in the table. If you don’t specify that it’s persisted, then the column’s value will be calculated each time you run a query against it.
You can query the sys.computed_columns system catalog view to find out whether a computed column is marked as persisted.
In SQL Server, you can use T-SQL to get the definition for a computed column by querying the sys.computed_columns system catalog view.
This article demonstrates how to use T-SQL to change an existing column to a computed column in SQL Server.
A computed column is a virtual column that uses an expression to calculate its value. The expression will typically use data from other columns. A computed column is not physically stored in the table unless it’s marked PERSISTED.
This article demonstrates how to use T-SQL to add a computed column to an existing table in SQL Server.
A computed column is a virtual column that uses an expression to calculate its value. The expression will typically use data from other columns. A computed column is not physically stored in the table unless it’s marked PERSISTED.
This article demonstrates how to use T-SQL to create a computed column in SQL Server.
A computed column is a virtual column that uses an expression to calculate its value. The expression will typically use data from other columns. A computed column is not physically stored in the table unless it’s marked PERSISTED.
You can use T-SQL to return a list of trigger events in a database in SQL Server.
You can do this using sys.trigger_events. This system catalog view returns a row for each event or event group on which a trigger can fire.
In SQL Server, you can use the T-SQL IDENT_CURRENT() function to return the last identity value generated for a specified table or view on an identity column. The last identity value generated can be for any session and any scope.
When you use T-SQL to create (or alter) a table in SQL Server, you have the option of using the IDENTITY() property to create an identity column.
An identity column contains an automatically incrementing identification number. The IDENTITY() property can be used with the CREATE TABLE and ALTER TABLE statements.
In SQL Server, you can use the IDENTITY() function to insert an identity column into a new table.
However, this function is not to be confused with the IDENTITY() property, which is used with the CREATE TABLE and ALTER TABLE statements.
The IDENTITY() function is used only in a SELECT statement with an INTO table clause. So you can use it when transferring data from one table to another, for example.
In SQL Server, you can use the sp_set_session_context stored procedure to set key/value pairs in the session context.
These key/value pairs then remain in your session context until your connection to SQL Server closes. You can use these values in stored procedures and other T-SQL code throughout the life of your session.
This method for maintaining session state was first introduced in SQL Server 2016. Prior to that release, you would need to use SET CONTEXT_INFO, which provides a similar, but much more limited way of storing session state.