/**
* This function IS NOT IMPLEMENTED. ONCE WE'LL BE USING RELATIONAL
* INTEGRITY IT WILL BECOME MORE USEFUL. FOR NOW, JUST CALCULATE "OFFICIAL"
* KEY NAMES WITHOUT ACCESSING TO DB AT ALL.
* Given one xmldb_key, the function returns the name of the key in DB (if exists)
* of false if it doesn't exist
*
* @param xmldb_table $xmldb_table The table to be searched.
* @param xmldb_key $xmldb_key The key to be searched.
* @return string key name if found
*/
public function find_key_name(xmldb_table $xmldb_table, xmldb_key $xmldb_key)
{
$keycolumns = $xmldb_key->getFields();
// Get list of keys in table
// first primaries (we aren't going to use this now, because the MetaPrimaryKeys is awful)
//TODO: To implement when we advance in relational integrity
// then uniques (note that Moodle, for now, shouldn't have any UNIQUE KEY for now, but unique indexes)
//TODO: To implement when we advance in relational integrity (note that AdoDB hasn't any MetaXXX for this.
// then foreign (note that Moodle, for now, shouldn't have any FOREIGN KEY for now, but indexes)
//TODO: To implement when we advance in relational integrity (note that AdoDB has one MetaForeignKeys()
//but it's far from perfect.
// TODO: To create the proper functions inside each generator to retrieve all the needed KEY info (name
// columns, reftable and refcolumns
// So all we do is to return the official name of the requested key without any confirmation!)
// One exception, hardcoded primary constraint names
if ($this->generator->primary_key_name && $xmldb_key->getType() == XMLDB_KEY_PRIMARY) {
return $this->generator->primary_key_name;
} else {
// Calculate the name suffix
switch ($xmldb_key->getType()) {
case XMLDB_KEY_PRIMARY:
$suffix = 'pk';
break;
case XMLDB_KEY_UNIQUE:
$suffix = 'uk';
break;
case XMLDB_KEY_FOREIGN_UNIQUE:
case XMLDB_KEY_FOREIGN:
$suffix = 'fk';
break;
}
// And simply, return the official name
return $this->generator->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), $suffix);
}
}
/**
* Given one correct xmldb_key, returns its specs.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_key.
* @param xmldb_key $xmldb_key The xmldb_key's specifications requested.
* @return string SQL statement about the xmldb_key.
*/
public function getKeySQL($xmldb_table, $xmldb_key)
{
$key = '';
switch ($xmldb_key->getType()) {
case XMLDB_KEY_PRIMARY:
if ($this->primary_keys) {
if ($this->primary_key_name !== null) {
$key = $this->getEncQuoted($this->primary_key_name);
} else {
$key = $this->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), 'pk');
}
$key .= ' PRIMARY KEY (' . implode(', ', $this->getEncQuoted($xmldb_key->getFields())) . ')';
}
break;
case XMLDB_KEY_UNIQUE:
if ($this->unique_keys) {
$key = $this->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), 'uk');
$key .= ' UNIQUE (' . implode(', ', $this->getEncQuoted($xmldb_key->getFields())) . ')';
}
break;
case XMLDB_KEY_FOREIGN:
case XMLDB_KEY_FOREIGN_UNIQUE:
if ($this->foreign_keys) {
$key = $this->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), 'fk');
$key .= ' FOREIGN KEY (' . implode(', ', $this->getEncQuoted($xmldb_key->getFields())) . ')';
$key .= ' REFERENCES ' . $this->getEncQuoted($this->prefix . $xmldb_key->getRefTable());
$key .= ' (' . implode(', ', $this->getEncQuoted($xmldb_key->getRefFields())) . ')';
}
break;
}
return $key;
}
/**
* Add one key to the table, allowing to specify the desired order
* If it's not specified, then the key is added at the end
* @param xmldb_key $key
* @param xmldb_object $after
*/
public function addKey($key, $after = null)
{
// Detect duplicates first
if ($this->getKey($key->getName())) {
throw new coding_exception('Duplicate key ' . $key->getName() . ' specified in table ' . $this->getName());
}
// Make sure there are no indexes with the key column specs because they would collide.
$newfields = $key->getFields();
$allindexes = $this->getIndexes();
foreach ($allindexes as $index) {
$fields = $index->getFields();
if ($fields === $newfields) {
throw new coding_exception('Index ' . $index->getName() . ' collides with key' . $key->getName() . ' specified in table ' . $this->getName());
}
}
// Calculate the previous and next keys
$prevkey = null;
$nextkey = null;
if (!$after) {
$allkeys = $this->getKeys();
if (!empty($allkeys)) {
end($allkeys);
$prevkey = $allkeys[key($allkeys)];
}
} else {
$prevkey = $this->getKey($after);
}
if ($prevkey && $prevkey->getNext()) {
$nextkey = $this->getKey($prevkey->getNext());
}
// Set current key previous and next attributes
if ($prevkey) {
$key->setPrevious($prevkey->getName());
$prevkey->setNext($key->getName());
}
if ($nextkey) {
$key->setNext($nextkey->getName());
$nextkey->setPrevious($key->getName());
}
// Some more attributes
$key->setLoaded(true);
$key->setChanged(true);
// Add the new key
$this->keys[] = $key;
// Reorder the keys
$this->orderKeys($this->keys);
// Recalculate the hash
$this->calculateHash(true);
// We have one new field, so the table has changed
$this->setChanged(true);
}
