DB_common::getOne()
Synopsis
mixed &getOne (
string $query
,
mixed $params = array()
)
Описание
Runs the query provided and returns the data from the first column of the first row then frees the result set.
Parameter
-
string
$query -
the SQL query or the statement to prepare
-
mixed
$params -
array, string or numeric data to be added to the prepared statement. Quantity of items passed must match quantity of placeholders in the prepared statement: meaning 1 placeholder for non-array parameters or 1 placeholder per array element.
If supplied, prepare()/ execute() is used.
Return value
mixed - the first column's data, NULL if there is no data, or a DB_Error object on failure
Throws
| Error code | Error message | Reason | Solution |
|---|---|---|---|
| DB_ERROR_INVALID | invalid | SQL statement for preparing is not valid. | See the prepare() documentation, if you want to use a SQL statemt using placeholders. |
| DB_ERROR_MISMATCH | mismatch | Quantity of parameters didn't match quantity of placeholders in the prepared statement. |
Check that the number of placeholders in the
prepare() statement passed to
$query equals the count of entries
passed to $params.
|
| DB_ERROR_NODBSELECTED | no database selected | No database was chosen. | Check the DSN in connect(). |
| every other error code | Database specific error | Check the database related section of PHP-Руководство to detect the reason for this error. In the most cases a misformed SQL statement. Ie. using LIMIT in a SQL-Statement for an Oracle database. |
Замечание
This function can not be called statically.
Пример
Using getOne()
<?php
// Once you have a valid DB object named $db...
$data =& $db->getOne('SELECT cf FROM foo');
if (PEAR::isError($data)) {
die($data->getMessage());
}
echo "$data\n";
?>
Using getOne() with one placeholder
<?php
// Once you have a valid DB object named $db...
$data =& $db->getOne('SELECT cf FROM foo WHERE nf = ?',
5);
if (PEAR::isError($data)) {
die($data->getMessage());
}
echo "$data\n";
?>
Using getOne() with two placeholders
<?php
// Once you have a valid DB object named $db...
$data =& $db->getOne('SELECT cf FROM foo WHERE nf IN (?, ?)',
array(5, 10));
if (PEAR::isError($data)) {
die($data->getMessage());
}
echo "$data\n";
?>