Updating multiple rows in sql server

Posted by / 08-Jan-2020 01:02

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.

Any characters not found in this code page are lost.

DEFAULT Specifies that the default value defined for the column is to replace the existing value in the column.

However, a large amount of data is more efficiently streamed into a file by using Win32 interfaces.

If the object being updated appears more than one time in the FROM clause, one, and only one, reference to the object must not specify a table alias.

Note Any call to OPENDATASOURCE, OPENQUERY, or OPENROWSET in the FROM clause is evaluated separately and independently from any call to these functions used as the target of the update, even if identical arguments are supplied to the two calls. Avoid using these hints in this context in new development work, and plan to modify applications that currently use them.

In particular, filter or join conditions applied on the result of one of those calls have no effect on the results of the other. Table2; USE Adventure Works2012; GO IF OBJECT_ID ('dbo. All char and nchar columns are right-padded to the defined length.

If the UPDATE statement affects multiple records, to return the old and new values for each record, use the OUTPUT clause. Table1 (Col A int NOT NULL, Col B decimal(10,3) NOT NULL); GO CREATE TABLE dbo. For example, a partial update of a varchar(max) column might delete or modify only the first 200 characters of the column, whereas a full update would delete or modify all the data in the column. WRITE updates that insert or append new data are minimally logged if the database recovery model is set to bulk-logged or simple.

Use caution when specifying the FROM clause to provide the criteria for the update operation. Table2 (Col A int PRIMARY KEY NOT NULL, Col B decimal(10,3) NOT NULL); GO INSERT INTO dbo. Minimal logging is not used when existing values are updated.

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All other references to the object in the FROM clause must include an object alias. Table1 (c1 int PRIMARY KEY NOT NULL, c2 int NOT NULL); GO CREATE TABLE dbo. Table2 WHERE CURRENT OF abc; GO SELECT c1, c2 FROM dbo.

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