PDO::errorInfo
You can't use it not only with SELECT statement, but any statement that might return rows. "OPTIMIZE table" is such example (returns some rows with optimization status).
If you do, PDO will lock-up with the "Cannot execute queries while other unbuffered queries are active." nonsense.
PDO::exec
(PHP 5 >= 5.1.0, PECL pdo >= 0.1.0)
PDO::exec — Execute an SQL statement and return the number of affected rows
Description
int PDO::exec
( string $statement
)
PDO::exec() executes an SQL statement in a single function call, returning the number of rows affected by the statement.
PDO::exec() does not return results from a SELECT statement. For a SELECT statement that you only need to issue once during your program, consider issuing PDO::query(). For a statement that you need to issue multiple times, prepare a PDOStatement object with PDO::prepare() and issue the statement with PDOStatement::execute().
Parameters
- statement
-
The SQL statement to prepare and execute.
Data inside the query should be properly escaped.
Return Values
PDO::exec() returns the number of rows that were modified or deleted by the SQL statement you issued. If no rows were affected, PDO::exec() returns 0.
Warning
This function may return Boolean FALSE, but may also return a non-Boolean value which evaluates to FALSE, such as 0 or "". Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.
The following example incorrectly relies on the return value of PDO::exec(), wherein a statement that affected 0 rows results in a call to die():
<?php
$db->exec() or die(print_r($db->errorInfo(), true));
?>
Examples
Example #1 Issuing a DELETE statement
Count the number of rows deleted by a DELETE statement with no WHERE clause.
<?php
$dbh = new PDO('odbc:sample', 'db2inst1', 'ibmdb2');
/* Delete all rows from the FRUIT table */
$count = $dbh->exec("DELETE FROM fruit WHERE colour = 'red'");
/* Return number of rows that were deleted */
print("Deleted $count rows.\n");
?>
The above example will output:
Deleted 1 rows.
See Also
- PDO::prepare() - Prepares a statement for execution and returns a statement object
- PDO::query() - Executes an SQL statement, returning a result set as a PDOStatement object
- PDOStatement::execute() - Executes a prepared statement
add a note
User Contributed NotesPDO::exec
blah at whatevr dot com
05-Sep-2007 01:07
05-Sep-2007 01:07
jon at chem dot umass dot edu
10-May-2007 07:12
10-May-2007 07:12
If you do this:
<?php
$res = $dbh->query("SELECT * FROM sessions WHERE session_id = '$p_sessID'");
$l_records = $res->fetch(PDO::FETCH_ASSOC);
if( $l_records ) {
// ...update session-data
$l_theQuery = "UPDATE sessions SET session_expires='$newExp', session_data='$p_sessData' WHERE session_id='$p_sessID'";
echo $l_theQuery;
$l_stmt = $this->db->prepare($l_theQuery);
if ( $l_stmt ) {
$l_rows = $l_stmt->execute();
}
}
?>
You will get nothing.
But do this:
<?php
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
?>
Prior to the code above, you will get this:
"PDO::prepare(): SQLSTATE[HY000]: General error: 2014 Cannot execute queries while other unbuffered queries are active. Consider using PDOStatement::fetchAll(). Alternatively, if your code is only ever going to run against mysql, you may enable query buffering by setting the PDO::MYSQL_ATTR_USE_BUFFERED_QUERY attribute."
So, instead of fetch(), use fetchAll(), it will make you less insane.
Incidentally, the INSERT statement that I was issuing, if the record that I needed to update didn't yet exist, after the initial fetch() command worked perfectly.
Changing to fetchAll() fixed it.
roberto at spadim dot com dot br
19-Dec-2006 05:47
19-Dec-2006 05:47
this function don't execute multi_query
to get it see SQLITE_EXEC comments there is an pereg function that get all queries and execute all then an return the last one
soletan at toxa dot de
29-Aug-2006 06:40
29-Aug-2006 06:40
It's worth noting here, that - in addition to the hints given in docs up there - using prepare, bind and execute provides more benefits than multiply querying a statement: performance and security!
If you insert some binary data (e.g. image file) into database using INSERT INTO ... then it may boost performance of parsing your statement since it is kept small (a few bytes, only, while the image may be several MiBytes) and there is no need to escape/quote the file's binary data to become a proper string value.
And, finally and for example, if you want to get a more secure PHP application which isn't affectable by SQL injection attacks you _have to_ consider using prepare/execute on every statement containing data (like INSERTs or SELECTs with WHERE-clauses). Separating the statement code from related data using prepare, bind and execute is best method - fast and secure! You don't even need to escape/quote/format-check any data.
david at acz dot org
09-Feb-2006 10:39
09-Feb-2006 10:39
This function cannot be used with any queries that return results. This includes SELECT, OPTIMIZE TABLE, etc.