Practical PostgreSQL

Declare

Defines a new cursor.

Synopsis

DECLARE  cursorname
    [ BINARY ] [ INSENSITIVE ] [ SCROLL ]
    CURSOR FOR query
    [ FOR { READ ONLY | UPDATE [ OF column [, ...] ] } ]

Parameters

cursorname

The name of the new cursor.

BINARY

The BINARY keyword causes the cursor to fetch data in binary format, rather than in the default text format.

INSENSITIVE

The INSENSITIVE keyword specifies that all data retrieved from the cursor will be unchanged by updates from other processes (and other cursors). This option is unneeded when using PostgreSQL, as the database already encapsulates all cursor operations within transactions. This option exists for compatibility with other database systems.

SCROLL

The SCROLL keyword allows data to be retrieved in multiple rows per FETCH operation. However, specifying it will have no effect, as PostgreSQL already allows this functionality implicitly.

query

The SQL query that will provide the new cursor with rows. For information on how to construct this query, see the reference entry titled “SELECT.”

READ ONLY

The READ ONLY clause indicates that the cursor will be used only to read data (read-only mode). Using this keyword has no effect, as PostgreSQL already only provides read-only access for use with cursors.

UPDATE

The UPDATE clause specifies that the cursor will be used to update tables; however, updates from cursors are not supported as of PostgreSQL 7.1.x (the current version at the printing of this book).

column

The columns to be updated; however, cursor updates are not currently ...