通过循环将一维数组转换为二维数组

Question

I'm trying to pull out all SQL tables and column into array, should look like this:

array(
 'tableName' => array(
      'column1',
      'column2',
      'column3',
  )
);

I have wrote this code that pull tables and columns names from the database and push it to array.

<?php
    include("db-config.php");
    $method = $_SERVER['REQUEST_METHOD'];
    $tablesQuery = mysqli_query($link,"SHOW TABLES");
    echo '<pre>';
    while($table = mysqli_fetch_assoc($tablesQuery)){
        $tables[] = $table['Tables_in_'.$DB['database']];
    }
    for($i = 0;$i<count($tables);$i++){
        $currentTable = $tables[$i];
        $columnsQuery = mysqli_query($link,"DESCRIBE `".$currentTable."`");
        while($column = mysqli_fetch_assoc($columnsQuery)){
            $tables[$i][] = $column['Field']; //line 13
        }
        print_r($currentTable);
    }
?>

on line 13 the syntax tables[$i] some how turn into string instand of staying array, so that stopped me from pushing columns's data inside.

Thank for your guys help!

Answer 1

For this task you need to query the INFORMATION_SCHEMA database and PDO to get the result in the proper format .

$sql = "SELECT TABLE_NAME, COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA='$DB[database]'";
$tables = $pdo->query($sql)->fetchAll(PDO::FETCH_GROUP|PDO::FETCH_COLUMN);

will give you the exact result you want.

Answer 2

You are not assigning the array correctly because $tables[$i] is a string value and not an array key:

$currentTable = $tables[$i]; // $tables[$i] is a string: you use it as a string below
mysqli_query($link,"DESCRIBE `".$currentTable."`"); //$currentTable = used as string

Then in your while loop, you attempt to use that string as an array key:

while($column = mysqli_fetch_assoc($columnsQuery)) {
    $tables[$i][] = $column['Field']; //$tables[$i] == $currentTable as above = string

What you need to do instead is assign the value using $currentTable as the key:

while($column = mysqli_fetch_assoc($columnsQuery)) {
    $tables[$currentTable][] = $column['Field'];
    // or
    $tables[$i][$currentTable][] = $column['Field'];