PostgreSQL 7.4.11 Documentation
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# SPI_exec

## Name

SPI_exec -- execute a command

## Synopsis

    int SPI_exec(const char * command, int count)

## Description

`SPI_exec` executes the specified SQL command for `count` rows.

This function should only be called from a connected procedure. If `count` is zero then it executes the command for all rows that it applies to. If `count` is greater than 0, then the number of rows for which the command will be executed is restricted (much like a `LIMIT` clause). For example,

    SPI_exec("INSERT INTO tab SELECT * FROM tab", 5);

will allow at most 5 rows to be inserted into the table.

You may pass multiple commands in one string, and the command may be rewritten by rules. `SPI_exec` returns the result for the command executed last.

The actual number of rows for which the (last) command was executed is returned in the global variable `SPI_processed` (unless the return value of the function is `SPI_OK_UTILITY`). If the return value of the function is `SPI_OK_SELECT` then you may the use global pointer `SPITupleTable *SPI_tuptable` to access the result rows.

The structure `SPITupleTable` is defined thus:

    typedef struct
    {
        MemoryContext tuptabcxt;    /* memory context of result table */
        uint32      alloced;        /* number of alloced vals */
        uint32      free;           /* number of free vals */
        TupleDesc   tupdesc;        /* row descriptor */
        HeapTuple  *vals;           /* rows */
    } SPITupleTable;

`vals` is an array of pointers to rows. (The number of valid entries is given by `SPI_processed`). `tupdesc` is a row descriptor which you may pass to SPI functions dealing with rows. `tuptabcxt`, `alloced`, and `free` are internal fields not intended for use by SPI callers.

`SPI_finish` frees all `SPITupleTable`s allocated during the current procedure. You can free a particular result table earlier, if you are done with it, by calling `SPI_freetuptable`.

## Arguments

`const char * `command``

  string containing command to execute

`int `count``

  maximum number of rows to process or return

## Return Value

If the execution of the command was successful then one of the following (nonnegative) values will be returned:

`SPI_OK_SELECT`

  if a `SELECT` (but not `SELECT ... INTO`) was executed

`SPI_OK_SELINTO`

  if a `SELECT ... INTO` was executed

`SPI_OK_DELETE`

  if a `DELETE` was executed

`SPI_OK_INSERT`

  if an `INSERT` was executed

`SPI_OK_UPDATE`

  if an `UPDATE` was executed

`SPI_OK_UTILITY`

  if a utility command (e.g., `CREATE TABLE`) was executed

On error, one of the following negative values is returned:

`SPI_ERROR_ARGUMENT`

  if `command` is `NULL` or `count` is less than 0

`SPI_ERROR_COPY`

  if `COPY TO stdout` or `COPY FROM stdin` was attempted

`SPI_ERROR_CURSOR`

  if `DECLARE`, `CLOSE`, or `FETCH` was attempted

`SPI_ERROR_TRANSACTION`

  if `BEGIN`, `COMMIT`, or `ROLLBACK` was attempted

`SPI_ERROR_OPUNKNOWN`

  if the command type is unknown (shouldn't happen)

`SPI_ERROR_UNCONNECTED`

  if called from an unconnected procedure

## Notes

The functions `SPI_exec`, `SPI_execp`, and `SPI_prepare` change both `SPI_processed` and `SPI_tuptable` (just the pointer, not the contents of the structure). Save these two global variables into local procedure variables if you need to access the result of `SPI_exec` or `SPI_execp` across later calls.

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