Updating multiple rows in sql server
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.
For more information about predicates and search conditions, see Search Condition (Transact-SQL). For more information, see SET ANSI_PADDING (Transact-SQL).When a FILESTREAM field is set to NULL, the BLOB data associated with the field is deleted. WRITE(), to perform partial updates to FILESTREAM data. If an update to a row violates a constraint or rule, violates the NULL setting for the column, or the new value is an incompatible data type, the statement is canceled, an error is returned, and no records are updated.