protected function findConstraints($table)
{
$sql = <<<SQL
SELECT D.CONSTRAINT_NAME, D.CONSTRAINT_TYPE, C.COLUMN_NAME, C.POSITION, D.R_CONSTRAINT_NAME,
E.TABLE_NAME AS TABLE_REF, F.COLUMN_NAME AS COLUMN_REF,
C.TABLE_NAME
FROM ALL_CONS_COLUMNS C
INNER JOIN ALL_CONSTRAINTS D ON D.OWNER = C.OWNER AND D.CONSTRAINT_NAME = C.CONSTRAINT_NAME
LEFT JOIN ALL_CONSTRAINTS E ON E.OWNER = D.R_OWNER AND E.CONSTRAINT_NAME = D.R_CONSTRAINT_NAME
LEFT JOIN ALL_CONS_COLUMNS F ON F.OWNER = E.OWNER AND F.CONSTRAINT_NAME = E.CONSTRAINT_NAME AND F.POSITION = C.POSITION
WHERE C.OWNER = :schemaName
AND C.TABLE_NAME = :tableName
ORDER BY D.CONSTRAINT_NAME, C.POSITION
SQL;
$command = $this->db->createCommand($sql, [':tableName' => $table->name, ':schemaName' => $table->schemaName]);
$constraints = [];
foreach ($command->queryAll() as $row) {
if ($this->db->slavePdo->getAttribute(\PDO::ATTR_CASE) === \PDO::CASE_LOWER) {
$row = array_change_key_case($row, CASE_UPPER);
}
if ($row['CONSTRAINT_TYPE'] === 'P') {
$table->columns[$row['COLUMN_NAME']]->isPrimaryKey = true;
$table->primaryKey[] = $row['COLUMN_NAME'];
if (empty($table->sequenceName)) {
$table->sequenceName = $this->getTableSequenceName($table->name);
}
}
if ($row['CONSTRAINT_TYPE'] !== 'R') {
// this condition is not checked in SQL WHERE because of an Oracle Bug:
// see https://github.com/yiisoft/yii2/pull/8844
continue;
}
$name = $row['CONSTRAINT_NAME'];
if (!isset($constraints[$name])) {
$constraints[$name] = ['tableName' => $row['TABLE_REF'], 'columns' => []];
}
$constraints[$name]['columns'][$row['COLUMN_NAME']] = $row['COLUMN_REF'];
}
foreach ($constraints as $constraint) {
$table->foreignKeys[] = array_merge([$constraint['tableName']], $constraint['columns']);
}
}