PHP注意：数组到字符串的转换

Question

I cannot seem to figure this out. I wrote a PHP script and I keep getting a Array to string conversion in... Notice as an error when trying to execute the postgres query:

$tables = array(array('a','table1'),array('c','table2'));
$table = $tables[0][1];
$query = "SELECT * FROM " . $table . " WHERE id = :id LIMIT 1";
$select = $dbconn->prepare($query);
$id = $_GET['id'];
if($select->execute()){
}else{
    echo $select->errorInfo();
}

I am using PostgreSQL version 9.2.1 and the latest PHP

Answer 1

PDOStatement::errorInfo() returns an array , but you are directly echoing it, which will always result in the string Array . You must store its returned array, and access the components you wish to read:

$err = $select->errorInfo();
print_r($err);

// Example as lifted from PHP docs linked above:
PDO::errorInfo():
Array
(
    [0] => HY000
    [1] => 1
    [2] => near "bogus": syntax error
)

Incidentally, the E_NOTICE for array to string conversion is new in PHP 5.4. The same code in PHP 5.3 would output Array as a string but would not issue the E_NOTICE .

Since you are using PHP 5.4, you can dereference the message [2] directly if you wish:

// 5.4+ only...
echo $select->errorInfo()[2];

Now why you are getting an error:

As to why you are entering the else block to report the error in the first place, you have a place holder for :id , but you never bound the variable $id before executing the query.

You may use

$select->execute(array(':id', $id))

Or

$select->bindParam(':id', $id, PDO::PARAM_INT); // assuming an integer $id. Use PDO::PARAM_STR for strings