Updating sql server
Specifies the temporary named result set or view, also known as common table expression (CTE), defined within the scope of the UPDATE statement.The CTE result set is derived from a simple query and is referenced by UPDATE statement.However, a large amount of data is more efficiently streamed into a file by using Win32 interfaces.When you update a FILESTREAM field, you modify the underlying BLOB data in the file system.The SQL Server (Transact-SQL) UPDATE statement is used to update existing records in a table in a SQL Server database.There are 3 syntaxes for the UPDATE statement depending on whether you are performing a traditional update or updating one table with data from another table.Use the @@ROWCOUNT function to return the number of inserted rows to the client application. Avoid using these data types in new development work, and plan to modify applications that currently use them.For more information, see @@ROWCOUNT (Transact-SQL). Variable names can be used in UPDATE statements to show the old and new values affected, but this should be used only when the UPDATE statement affects a single record. Use nvarchar(max), varchar(max), and varbinary(max) instead. ) clause to perform a partial or full update of varchar(max), nvarchar(max), and varbinary(max) data types.
For example, in the UPDATE statement in the following script, both rows in USE Adventure Works2012; GO IF OBJECT_ID ('dbo. The Database Engine converts a partial update to a full update when the UPDATE statement causes either of these actions: are specified in bytes for varbinary and varchar data types and in characters for the nvarchar data type.
CURRENT OF Specifies that the update is performed at the current position of the specified cursor. Modifying a text, ntext, or image column with UPDATE initializes the column, assigns a valid text pointer to it, and allocates at least one data page, unless the column is being updated with NULL.
A positioned update using a WHERE CURRENT OF clause updates the single row at the current position of the cursor. To replace or modify large blocks of text, ntext, or image data, use WRITETEXT or UPDATETEXT instead of the UPDATE statement.
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DEFAULT Specifies that the default value defined for the column is to replace the existing value in the column.