DECLARE

Create a cursor.

Synopsis

DECLARE name [ ASENSITIVE | INSENSITIVE ] [ [ NO ] SCROLL ]
CURSOR [ { WITH | WITHOUT } HOLD ] FOR query

Where name is an arbitrary name for the cursor and query is a SELECT statement.

Description

A cursor is used to retrieve a small number of rows at a time from a query with a larger result set. After creating a cursor, rows are fetched using FETCH.

See also

FETCH CLOSE

Clauses

WITH | WITHOUT HOLD

Defaults to WITHOUT HOLD, causing a cursor to be bound to the life-time of a transaction. Using WITHOUT HOLD without active transaction (Started with BEGIN) is an error.

WITH HOLD changes the life-time of a cursor to that of the connection.

Committing a transaction closes all cursors created with WITHOUT HOLD. Closing a connection closes all cursors created within that connection.

Note

CrateDB doesn’t support full transactions. A transaction cannot be rolled back and any write operations within a BEGIN clause may become visible to other statements before committing the transaction.

[ ASENSITIVE | INSENSITIVE ]

This clause has no effect in CrateDB Cursors in CrateDB are always insensitive.

[ NO ] SCROLL

NO SCROLL (the default) specifies that the cursor can only be used to move forward.

SCROLL is currently not supported.

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