/**
* Parse a a single column or index definition.
*
* This function can parse many (but not all) types of syntax used to define columns
* and indexes in a "CREATE TABLE" query.
*
* @param string $line
* @return array
*/
function parse_create_definition($line)
{
$line = preg_replace('@[,\\r\\n\\s]+$@', '', $line);
//Strip the ", " line separator
$pieces = preg_split('@\\s+|(?=\\()@', $line, -1, PREG_SPLIT_NO_EMPTY);
if (empty($pieces)) {
return null;
}
$token = strtolower(array_shift($pieces));
$index_modifier = '';
$index = false;
//Determine if this line defines an index
if (in_array($token, array('primary', 'unique', 'fulltext'))) {
$index_modifier = $token;
$index = true;
$token = strtolower(array_shift($pieces));
}
if (in_array($token, array('index', 'key'))) {
$index = true;
$token = strtolower(array_shift($pieces));
}
//Determine column/index name
$name = '';
if ($index) {
//Names are optional for indexes; the INDEX/etc keyword can be immediately
//followed by a column list (or index_type, but we're ignoring that possibility).
if (strpos($token, '(') === false) {
$name = $token;
} else {
if ($index_modifier == 'primary') {
$name = 'primary';
}
array_unshift($pieces, $token);
}
} else {
$name = $token;
}
$name = strtolower(trim($name, '`'));
$definition = compact('name', 'index', 'index_modifier');
//Parse the rest of the line
$remainder = implode(' ', $pieces);
if ($index) {
$definition['columns'] = blcTableDelta::parse_index_column_list($remainder);
//If the index doesn't have a name, use the name of the first column
//(this is what MySQL does, but only when there isn't already an index with that name).
if (empty($definition['name'])) {
$definition['name'] = $definition['columns'][0]['column_name'];
}
//Rebuild the index def. in a normalized form
$definition['index_definition'] = blcTableDelta::generate_index_string($definition);
} else {
$column_def = blcTableDelta::parse_column_definition($remainder);
$definition = array_merge($definition, $column_def);
}
return $definition;
}
