SPI_CURSOR_OPEN(3) PostgreSQL 9.1.9 Documentation SPI_CURSOR_OPEN(3)NAMESPI_cursor_open - set up a cursor using a plan created with SPI_prepare
SYNOPSIS
Portal SPI_cursor_open(const char * name, SPIPlanPtr plan,
Datum * values, const char * nulls,
bool read_only)
DESCRIPTIONSPI_cursor_open sets up a cursor (internally, a portal) that will
execute a plan prepared by SPI_prepare. The parameters have the same
meanings as the corresponding parameters to SPI_execute_plan.
Using a cursor instead of executing the plan directly has two benefits.
First, the result rows can be retrieved a few at a time, avoiding
memory overrun for queries that return many rows. Second, a portal can
outlive the current procedure (it can, in fact, live to the end of the
current transaction). Returning the portal name to the procedure's
caller provides a way of returning a row set as result.
The passed-in parameter data will be copied into the cursor's portal,
so it can be freed while the cursor still exists.
ARGUMENTS
const char * name
name for portal, or NULL to let the system select a name
SPIPlanPtr plan
execution plan (returned by SPI_prepare)
Datum * values
An array of actual parameter values. Must have same length as the
plan's number of arguments.
const char * nulls
An array describing which parameters are null. Must have same
length as the plan's number of arguments. n indicates a null value
(entry in values will be ignored); a space indicates a nonnull
value (entry in values is valid).
If nulls is NULL then SPI_cursor_open assumes that no parameters
are null.
bool read_only
true for read-only execution
RETURN VALUE
Pointer to portal containing the cursor. Note there is no error return
convention; any error will be reported via elog.
PostgreSQL 9.1.9 2013-04-01 SPI_CURSOR_OPEN(3)
