Chapter 9 SQL Statements
571
If cursor-name is specified by an identifier or string, the corresponding
DECLARE CURSOR must appear prior to the OPEN in the C program; if
the cursor-name is specified by a host variable, the DECLARE CURSOR
statement must execute before the OPEN statement.
USING DESCRIPTOR clause The USING DESCRIPTOR clause is for
Embedded SQL only. It specifies the host variables to be bound to the place-
holder bind variables in the SELECT statement for which the cursor has been
declared.
WITH HOLD clause By default, all cursors are automatically closed at the
end of the current transaction (COMMIT or ROLLBACK). The optional
WITH HOLD clause keeps the cursor open for subsequent transactions. It
will remain open until the end of the current connection or until an explicit
CLOSE statement is executed. Cursors are automatically closed when a
connection is terminated.
ISOLATION LEVEL clause The ISOLATION LEVEL clause allows this
cursor to be opened at an isolation level different from the current setting of
the ISOLATION_LEVEL option. All operations on this cursor will be
performed at the specified isolation level regardless of the option setting. If
this clause is not specified, then the cursor’s isolation level for the entire time
the cursor is open is the value of the ISOLATION_LEVEL option when the
cursor is opened. See "How locking works" on page 413 of the book ASA
User’s Guide.
The cursor is positioned before the first row (see "Cursors in Embedded
SQL" on page 33 of the book ASA Programming Interfaces Guide or "Using
cursors in procedures and triggers" on page 471 of the book ASA User’s
Guide).
BLOCK clause This clause is for Embedded SQL use only. Rows are
fetched by the client application in blocks (more than one at a time). By
default, the number of rows in a block is determined dynamically based on
the size of the rows and how long it takes the database server to fetch each
row. The application can specify a maximum number of rows that should be
contained in a block by specifying the BLOCK clause. For example, if you
are fetching and displaying 5 rows at a time, use BLOCK 5. Specifying
BLOCK 0 will cause one row at a time to be fetched, and also cause a
FETCH RELATIVE 0 to always fetch the row again.
$ For more information, see "FETCH statement" on page 523.
♦
SQL/92 Embedded SQL use is an entry-level feature. Procedures use
is a Persistent Stored Modules feature.
Standards and
compatibility
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