/**
* Adds extra indices for reverse foreign keys
* This is required for MySQL databases,
* and is called from Database::doFinalInitialization()
*/
public function addExtraIndices()
{
/**
* A collection of indexed columns. The keys is the column name
* (concatenated with a comma in the case of multi-col index), the value is
* an array with the names of the indexes that index these columns. We use
* it to determine which additional indexes must be created for foreign
* keys. It could also be used to detect duplicate indexes, but this is not
* implemented yet.
* @var array
*/
$_indices = array();
$this->collectIndexedColumns('PRIMARY', $this->getPrimaryKey(), $_indices);
$_tableIndices = array_merge($this->getIndices(), $this->getUnices());
foreach ($_tableIndices as $_index) {
$this->collectIndexedColumns($_index->getName(), $_index->getColumns(), $_indices);
}
// we're determining which tables have foreign keys that point to this table,
// since MySQL needs an index on any column that is referenced by another table
// (yep, MySQL _is_ a PITA)
$counter = 0;
foreach ($this->getReferrers() as $foreignKey) {
$referencedColumns = $foreignKey->getForeignColumnObjects();
$referencedColumnsHash = $this->getColumnList($referencedColumns);
if (!array_key_exists($referencedColumnsHash, $_indices)) {
// no matching index defined in the schema, so we have to create one
$index = new Index();
$index->setName(sprintf('I_referenced_%s_%s', $foreignKey->getName(), ++$counter));
$index->setColumns($referencedColumns);
$index->resetColumnSize();
$this->addIndex($index);
// Add this new index to our collection, otherwise we might add it again (bug #725)
$this->collectIndexedColumns($index->getName(), $referencedColumns, $_indices);
}
}
// we're adding indices for this table foreign keys
foreach ($this->getForeignKeys() as $foreignKey) {
$localColumns = $foreignKey->getLocalColumnObjects();
$localColumnsHash = $this->getColumnList($localColumns);
if (!array_key_exists($localColumnsHash, $_indices)) {
// no matching index defined in the schema, so we have to create one. MySQL needs indices on any columns that serve as foreign keys. these are not auto-created prior to 4.1.2
$index = new Index();
$index->setName(substr_replace($foreignKey->getName(), 'FI_', strrpos($foreignKey->getName(), 'FK_'), 3));
$index->setColumns($localColumns);
$index->resetColumnSize();
$this->addIndex($index);
$this->collectIndexedColumns($index->getName(), $localColumns, $_indices);
}
}
}
