silverstripe-framework/model/Database.php
Mateusz Uzdowski 8eb0fa91bd API Add the ability to query if the schema update is in progress.
The specific situation where this is useful is where populateDefaults on
DataObjects needs to query the database. This will break the dev/build
when it tries to create the object via singleton - the query will not be
able to be executed if the table is not there or its schema has changed.

For an example of such use case see Translatable::populateDefaults.
2012-10-17 11:45:21 +13:00

1240 lines
38 KiB
PHP

<?php
/**
* Abstract database connectivity class.
* Sub-classes of this implement the actual database connection libraries
* @package framework
* @subpackage model
*/
abstract class SS_Database {
/**
* Connection object to the database.
* @param resource
*/
static $globalConn;
/**
* @var boolean Check tables when running /dev/build, and repair them if necessary.
* In case of large databases or more fine-grained control on how to handle
* data corruption in tables, you can disable this behaviour and handle it
* outside of this class, e.g. through a nightly system task with extended logging capabilities.
*/
static $check_and_repair_on_build = true;
/**
* If this is false, then information about database operations
* will be displayed, eg creation of tables.
* @param boolean
*/
protected $supressOutput = false;
/**
* Execute the given SQL query.
* This abstract function must be defined by subclasses as part of the actual implementation.
* It should return a subclass of SS_Query as the result.
* @param string $sql The SQL query to execute
* @param int $errorLevel The level of error reporting to enable for the query
* @return SS_Query
*/
abstract public function query($sql, $errorLevel = E_USER_ERROR);
/**
* Get the autogenerated ID from the previous INSERT query.
* @return int
*/
abstract public function getGeneratedID($table);
/**
* Check if the connection to the database is active.
* @return boolean
*/
abstract public function isActive();
/**
* Create the database and connect to it. This can be called if the
* initial database connection is not successful because the database
* does not exist.
*
* It takes no parameters, and should create the database from the information
* specified in the constructor.
*
* @return boolean Returns true if successful
*/
abstract public function createDatabase();
/**
* Build the connection string from input
* @param array $parameters The connection details
* @return string $connect The connection string
**/
abstract public function getConnect($parameters);
/**
* Create a new table.
* @param $tableName The name of the table
* @param $fields A map of field names to field types
* @param $indexes A map of indexes
* @param $options An map of additional options. The available keys are as follows:
* - 'MSSQLDatabase'/'MySQLDatabase'/'PostgreSQLDatabase' - database-specific options such as "engine" for MySQL.
* - 'temporary' - If true, then a temporary table will be created
* @return The table name generated. This may be different from the table name, for example with temporary tables.
*/
abstract public function createTable($table, $fields = null, $indexes = null, $options = null,
$advancedOptions = null);
/**
* Alter a table's schema.
*/
abstract public function alterTable($table, $newFields = null, $newIndexes = null, $alteredFields = null,
$alteredIndexes = null, $alteredOptions=null, $advancedOptions=null);
/**
* Rename a table.
* @param string $oldTableName The old table name.
* @param string $newTableName The new table name.
*/
abstract public function renameTable($oldTableName, $newTableName);
/**
* Create a new field on a table.
* @param string $table Name of the table.
* @param string $field Name of the field to add.
* @param string $spec The field specification, eg 'INTEGER NOT NULL'
*/
abstract public function createField($table, $field, $spec);
/**
* Change the database column name of the given field.
*
* @param string $tableName The name of the tbale the field is in.
* @param string $oldName The name of the field to change.
* @param string $newName The new name of the field
*/
abstract public function renameField($tableName, $oldName, $newName);
/**
* Get a list of all the fields for the given table.
* Returns a map of field name => field spec.
* @param string $table The table name.
* @return array
*/
abstract protected function fieldList($table);
/**
* Returns a list of all tables in the database.
* Keys are table names in lower case, values are table names in case that
* database expects.
* @return array
*/
/**
*
* This is a stub function. Postgres caches the fieldlist results.
*
* @param string $tableName
*
* @return boolean
*/
public function clearCachedFieldlist($tableName=false){
return true;
}
abstract protected function tableList();
/**
* Returns true if the given table exists in the database
*/
abstract public function hasTable($tableName);
/**
* Returns the enum values available on the given field
*/
abstract public function enumValuesForField($tableName, $fieldName);
/**
* Returns an escaped string.
*
* @param string
* @return string - escaped string
*/
abstract public function addslashes($val);
/**
* The table list, generated by the tableList() function.
* Used by the requireTable() function.
* @var array
*/
protected $tableList;
/**
* The field list, generated by the fieldList() function.
* An array of maps of field name => field spec, indexed
* by table name.
* @var array
*/
protected $fieldList;
/**
* The index list for each table, generated by the indexList() function.
* An map from table name to an array of index names.
* @var array
*/
protected $indexList;
/**
* Keeps track whether we are currently updating the schema.
*/
protected $schemaIsUpdating = false;
/**
* Large array structure that represents a schema update transaction
*/
protected $schemaUpdateTransaction;
/**
* Start a schema-updating transaction.
* All calls to requireTable/Field/Index will keep track of the changes requested, but not actually do anything.
* Once
*/
public function beginSchemaUpdate() {
$this->schemaIsUpdating = true;
$this->tableList = array();
$tables = $this->tableList();
foreach($tables as $table) $this->tableList[strtolower($table)] = $table;
$this->indexList = null;
$this->fieldList = null;
$this->schemaUpdateTransaction = array();
}
/**
* Completes a schema-updated transaction, executing all the schema chagnes.
*/
public function endSchemaUpdate() {
foreach($this->schemaUpdateTransaction as $tableName => $changes) {
switch($changes['command']) {
case 'create':
$this->createTable($tableName, $changes['newFields'], $changes['newIndexes'], $changes['options'],
@$changes['advancedOptions']);
break;
case 'alter':
$this->alterTable($tableName, $changes['newFields'], $changes['newIndexes'],
$changes['alteredFields'], $changes['alteredIndexes'], $changes['alteredOptions'],
@$changes['advancedOptions']);
break;
}
}
$this->schemaUpdateTransaction = null;
$this->schemaIsUpdating = false;
}
/**
* Cancels the schema updates requested after a beginSchemaUpdate() call.
*/
public function cancelSchemaUpdate() {
$this->schemaUpdateTransaction = null;
$this->schemaIsUpdating = false;
}
/**
* Returns true if we are during a schema update.
*/
function isSchemaUpdating() {
return $this->schemaIsUpdating;
}
/**
* Returns true if schema modifications were requested after a beginSchemaUpdate() call.
*/
public function doesSchemaNeedUpdating() {
return (bool)$this->schemaUpdateTransaction;
}
// Transactional schema altering functions - they don't do anyhting except for update schemaUpdateTransaction
/**
* @param string $table
* @param string $options
*/
public function transCreateTable($table, $options = null, $advanced_options = null) {
$this->schemaUpdateTransaction[$table] = array(
'command' => 'create',
'newFields' => array(),
'newIndexes' => array(),
'options' => $options,
'advancedOptions' => $advanced_options
);
}
/**
* @param string $table
* @param array $options
*/
public function transAlterTable($table, $options, $advanced_options) {
$this->transInitTable($table);
$this->schemaUpdateTransaction[$table]['alteredOptions'] = $options;
$this->schemaUpdateTransaction[$table]['advancedOptions'] = $advanced_options;
}
public function transCreateField($table, $field, $schema) {
$this->transInitTable($table);
$this->schemaUpdateTransaction[$table]['newFields'][$field] = $schema;
}
public function transCreateIndex($table, $index, $schema) {
$this->transInitTable($table);
$this->schemaUpdateTransaction[$table]['newIndexes'][$index] = $schema;
}
public function transAlterField($table, $field, $schema) {
$this->transInitTable($table);
$this->schemaUpdateTransaction[$table]['alteredFields'][$field] = $schema;
}
public function transAlterIndex($table, $index, $schema) {
$this->transInitTable($table);
$this->schemaUpdateTransaction[$table]['alteredIndexes'][$index] = $schema;
}
/**
* Handler for the other transXXX methods - mark the given table as being altered
* if it doesn't already exist
*/
protected function transInitTable($table) {
if(!isset($this->schemaUpdateTransaction[$table])) {
$this->schemaUpdateTransaction[$table] = array(
'command' => 'alter',
'newFields' => array(),
'newIndexes' => array(),
'alteredFields' => array(),
'alteredIndexes' => array(),
'alteredOptions' => ''
);
}
}
/**
* Generate the following table in the database, modifying whatever already exists
* as necessary.
* @todo Change detection for CREATE TABLE $options other than "Engine"
*
* @param string $table The name of the table
* @param string $fieldSchema A list of the fields to create, in the same form as DataObject::$db
* @param string $indexSchema A list of indexes to create. See {@link requireIndex()}
* @param array $options
*/
public function requireTable($table, $fieldSchema = null, $indexSchema = null, $hasAutoIncPK=true,
$options = Array(), $extensions=false) {
if(!isset($this->tableList[strtolower($table)])) {
$this->transCreateTable($table, $options, $extensions);
$this->alterationMessage("Table $table: created","created");
} else {
if(self::$check_and_repair_on_build) $this->checkAndRepairTable($table, $options);
// Check if options changed
$tableOptionsChanged = false;
if(isset($options[get_class($this)]) || true) {
if(isset($options[get_class($this)])) {
if(preg_match('/ENGINE=([^\s]*)/', $options[get_class($this)], $alteredEngineMatches)) {
$alteredEngine = $alteredEngineMatches[1];
$tableStatus = DB::query(sprintf(
'SHOW TABLE STATUS LIKE \'%s\'',
$table
))->first();
$tableOptionsChanged = ($tableStatus['Engine'] != $alteredEngine);
}
}
}
if($tableOptionsChanged || ($extensions && DB::getConn()->supportsExtensions()))
$this->transAlterTable($table, $options, $extensions);
}
//DB ABSTRACTION: we need to convert this to a db-specific version:
$this->requireField($table, 'ID', DB::getConn()->IdColumn(false, $hasAutoIncPK));
// Create custom fields
if($fieldSchema) {
foreach($fieldSchema as $fieldName => $fieldSpec) {
//Is this an array field?
$arrayValue='';
if(strpos($fieldSpec, '[')!==false){
//If so, remove it and store that info separately
$pos=strpos($fieldSpec, '[');
$arrayValue=substr($fieldSpec, $pos);
$fieldSpec=substr($fieldSpec, 0, $pos);
}
$fieldObj = Object::create_from_string($fieldSpec, $fieldName);
$fieldObj->arrayValue=$arrayValue;
$fieldObj->setTable($table);
$fieldObj->requireField();
}
}
// Create custom indexes
if($indexSchema) {
foreach($indexSchema as $indexName => $indexDetails) {
$this->requireIndex($table, $indexName, $indexDetails);
}
}
}
/**
* If the given table exists, move it out of the way by renaming it to _obsolete_(tablename).
* @param string $table The table name.
*/
public function dontRequireTable($table) {
if(isset($this->tableList[strtolower($table)])) {
$suffix = '';
while(isset($this->tableList[strtolower("_obsolete_{$table}$suffix")])) {
$suffix = $suffix ? ($suffix+1) : 2;
}
$this->renameTable($table, "_obsolete_{$table}$suffix");
$this->alterationMessage("Table $table: renamed to _obsolete_{$table}$suffix","obsolete");
}
}
/**
* Generate the given index in the database, modifying whatever already exists as necessary.
*
* The keys of the array are the names of the index.
* The values of the array can be one of:
* - true: Create a single column index on the field named the same as the index.
* - array('type' => 'index|unique|fulltext', 'value' => 'FieldA, FieldB'): This gives you full
* control over the index.
*
* @param string $table The table name.
* @param string $index The index name.
* @param string|boolean $spec The specification of the index. See requireTable() for more information.
*/
public function requireIndex($table, $index, $spec) {
$newTable = false;
//DB Abstraction: remove this ===true option as a possibility?
if($spec === true) {
$spec = "(\"$index\")";
}
//Indexes specified as arrays cannot be checked with this line: (it flattens out the array)
if(!is_array($spec)) {
$spec = preg_replace('/\s*,\s*/', ',', $spec);
}
if(!isset($this->tableList[strtolower($table)])) $newTable = true;
if(!$newTable && !isset($this->indexList[$table])) {
$this->indexList[$table] = $this->indexList($table);
}
//Fix up the index for database purposes
$index=DB::getConn()->getDbSqlDefinition($table, $index, null, true);
//Fix the key for database purposes
$index_alt=DB::getConn()->modifyIndex($index, $spec);
if(!$newTable) {
if(isset($this->indexList[$table][$index_alt])) {
if(is_array($this->indexList[$table][$index_alt])) {
$array_spec = $this->indexList[$table][$index_alt]['spec'];
} else {
$array_spec = $this->indexList[$table][$index_alt];
}
}
}
if($newTable || !isset($this->indexList[$table][$index_alt])) {
$this->transCreateIndex($table, $index, $spec);
$this->alterationMessage("Index $table.$index: created as "
. DB::getConn()->convertIndexSpec($spec),"created");
} else if($array_spec != DB::getConn()->convertIndexSpec($spec)) {
$this->transAlterIndex($table, $index, $spec);
$spec_msg=DB::getConn()->convertIndexSpec($spec);
$this->alterationMessage("Index $table.$index: changed to $spec_msg"
. " <i style=\"color: #AAA\">(from {$array_spec})</i>","changed");
}
}
/**
* Return true if the table exists and already has a the field specified
* @param string $tableName - The table to check
* @param string $fieldName - The field to check
* @return bool - True if the table exists and the field exists on the table
*/
public function hasField($tableName, $fieldName) {
if (!$this->hasTable($tableName)) return false;
$fields = $this->fieldList($tableName);
return array_key_exists($fieldName, $fields);
}
/**
* Generate the given field on the table, modifying whatever already exists as necessary.
* @param string $table The table name.
* @param string $field The field name.
* @param array|string $spec The field specification. If passed in array syntax, the specific database
* driver takes care of the ALTER TABLE syntax. If passed as a string, its assumed to
* be prepared as a direct SQL framgment ready for insertion into ALTER TABLE. In this case you'll
* need to take care of database abstraction in your DBField subclass.
*/
public function requireField($table, $field, $spec) {
//TODO: this is starting to get extremely fragmented.
//There are two different versions of $spec floating around, and their content changes depending
//on how they are structured. This needs to be tidied up.
$fieldValue = null;
$newTable = false;
Profiler::mark('requireField');
// backwards compatibility patch for pre 2.4 requireField() calls
$spec_orig=$spec;
if(!is_string($spec)) {
$spec['parts']['name'] = $field;
$spec_orig['parts']['name'] = $field;
//Convert the $spec array into a database-specific string
$spec=DB::getConn()->$spec['type']($spec['parts'], true);
}
// Collations didn't come in until MySQL 4.1. Anything earlier will throw a syntax error if you try and use
// collations.
// TODO: move this to the MySQLDatabase file, or drop it altogether?
if(!$this->supportsCollations()) {
$spec = preg_replace('/ *character set [^ ]+( collate [^ ]+)?( |$)/', '\\2', $spec);
}
if(!isset($this->tableList[strtolower($table)])) $newTable = true;
if(!$newTable && !isset($this->fieldList[$table])) {
$this->fieldList[$table] = $this->fieldList($table);
}
if(is_array($spec)) {
$specValue = DB::getConn()->$spec_orig['type']($spec_orig['parts']);
} else {
$specValue = $spec;
}
// We need to get db-specific versions of the ID column:
if($spec_orig==DB::getConn()->IdColumn() || $spec_orig==DB::getConn()->IdColumn(true))
$specValue=DB::getConn()->IdColumn(true);
if(!$newTable) {
if(isset($this->fieldList[$table][$field])) {
if(is_array($this->fieldList[$table][$field])) {
$fieldValue = $this->fieldList[$table][$field]['data_type'];
} else {
$fieldValue = $this->fieldList[$table][$field];
}
}
}
// Get the version of the field as we would create it. This is used for comparison purposes to see if the
// existing field is different to what we now want
if(is_array($spec_orig)) {
$spec_orig=DB::getConn()->$spec_orig['type']($spec_orig['parts']);
}
if($newTable || $fieldValue=='') {
Profiler::mark('createField');
$this->transCreateField($table, $field, $spec_orig);
Profiler::unmark('createField');
$this->alterationMessage("Field $table.$field: created as $spec_orig","created");
} else if($fieldValue != $specValue) {
// If enums/sets are being modified, then we need to fix existing data in the table.
// Update any records where the enum is set to a legacy value to be set to the default.
// One hard-coded exception is SiteTree - the default for this is Page.
foreach(array('enum','set') as $enumtype) {
if(preg_match("/^$enumtype/i",$specValue)) {
$newStr = preg_replace("/(^$enumtype\s*\(')|('$\).*)/i","",$spec_orig);
$new = preg_split("/'\s*,\s*'/", $newStr);
$oldStr = preg_replace("/(^$enumtype\s*\(')|('$\).*)/i","", $fieldValue);
$old = preg_split("/'\s*,\s*'/", $newStr);
$holder = array();
foreach($old as $check) {
if(!in_array($check, $new)) {
$holder[] = $check;
}
}
if(count($holder)) {
$default = explode('default ', $spec_orig);
$default = $default[1];
if($default == "'SiteTree'") $default = "'Page'";
$query = "UPDATE \"$table\" SET $field=$default WHERE $field IN (";
for($i=0;$i+1<count($holder);$i++) {
$query .= "'{$holder[$i]}', ";
}
$query .= "'{$holder[$i]}')";
DB::query($query);
$amount = DB::affectedRows();
$this->alterationMessage("Changed $amount rows to default value of field $field"
. " (Value: $default)");
}
}
}
Profiler::mark('alterField');
$this->transAlterField($table, $field, $spec_orig);
Profiler::unmark('alterField');
$this->alterationMessage("Field $table.$field: changed to $specValue"
. " <i style=\"color: #AAA\">(from {$fieldValue})</i>","changed");
}
Profiler::unmark('requireField');
}
/**
* If the given field exists, move it out of the way by renaming it to _obsolete_(fieldname).
*
* @param string $table
* @param string $fieldName
*/
public function dontRequireField($table, $fieldName) {
$fieldList = $this->fieldList($table);
if(array_key_exists($fieldName, $fieldList)) {
$suffix = '';
while(isset($fieldList[strtolower("_obsolete_{$fieldName}$suffix")])) {
$suffix = $suffix ? ($suffix+1) : 2;
}
$this->renameField($table, $fieldName, "_obsolete_{$fieldName}$suffix");
$this->alterationMessage("Field $table.$fieldName: renamed to $table._obsolete_{$fieldName}$suffix",
"obsolete");
}
}
/**
* Execute a complex manipulation on the database.
* A manipulation is an array of insert / or update sequences. The keys of the array are table names,
* and the values are map containing 'command' and 'fields'. Command should be 'insert' or 'update',
* and fields should be a map of field names to field values, including quotes. The field value can
* also be a SQL function or similar.
* @param array $manipulation
*/
public function manipulate($manipulation) {
if($manipulation) foreach($manipulation as $table => $writeInfo) {
if(isset($writeInfo['fields']) && $writeInfo['fields']) {
$fieldList = $columnList = $valueList = array();
foreach($writeInfo['fields'] as $fieldName => $fieldVal) {
$fieldList[] = "\"$fieldName\" = $fieldVal";
$columnList[] = "\"$fieldName\"";
// Empty strings inserted as null in INSERTs. Replacement of SS_Database::replace_with_null().
if($fieldVal === "''") $valueList[] = "null";
else $valueList[] = $fieldVal;
}
if(!isset($writeInfo['where']) && isset($writeInfo['id'])) {
$writeInfo['where'] = "\"ID\" = " . (int)$writeInfo['id'];
}
switch($writeInfo['command']) {
case "update":
// Test to see if this update query shouldn't, in fact, be an insert
if($this->query("SELECT \"ID\" FROM \"$table\" WHERE $writeInfo[where]")->value()) {
$fieldList = implode(", ", $fieldList);
$sql = "UPDATE \"$table\" SET $fieldList where $writeInfo[where]";
$this->query($sql);
break;
}
// ...if not, we'll skip on to the insert code
case "insert":
if(!isset($writeInfo['fields']['ID']) && isset($writeInfo['id'])) {
$columnList[] = "\"ID\"";
$valueList[] = (int)$writeInfo['id'];
}
$columnList = implode(", ", $columnList);
$valueList = implode(", ", $valueList);
$sql = "INSERT INTO \"$table\" ($columnList) VALUES ($valueList)";
$this->query($sql);
break;
default:
$sql = null;
user_error("SS_Database::manipulate() Can't recognise command '$writeInfo[command]'",
E_USER_ERROR);
}
}
}
}
/** Replaces "\'\'" with "null", recursively walks through the given array.
* @param string $array Array where the replacement should happen
*/
public static function replace_with_null(&$array) {
$array = preg_replace('/= *\'\'/', '= null', $array);
if(is_array($array)) {
foreach($array as $key => $value) {
if(is_array($value)) {
array_walk($array, array(SS_Database, 'replace_with_null'));
}
}
}
return $array;
}
/**
* Error handler for database errors.
* All database errors will call this function to report the error. It isn't a static function;
* it will be called on the object itself and as such can be overridden in a subclass.
* @todo hook this into a more well-structured error handling system.
* @param string $msg The error message.
* @param int $errorLevel The level of the error to throw.
*/
public function databaseError($msg, $errorLevel = E_USER_ERROR) {
user_error($msg, $errorLevel);
}
/**
* Enable supression of database messages.
*/
public function quiet() {
$this->supressOutput = true;
}
/**
* Show a message about database alteration
*
* @param string message to display
* @param string type one of [created|changed|repaired|obsolete|deleted|error]
*/
public function alterationMessage($message,$type=""){
if(!$this->supressOutput) {
if(Director::is_cli()) {
switch ($type){
case "created":
case "changed":
case "repaired":
$sign = "+";
break;
case "obsolete":
case "deleted":
$sign = '-';
break;
case "error":
$sign = "!";
break;
default:
$sign=" ";
}
$message = strip_tags($message);
echo " $sign $message\n";
} else {
switch ($type){
case "created":
$color = "green";
break;
case "obsolete":
$color = "red";
break;
case "error":
$color = "red";
break;
case "deleted":
$color = "red";
break;
case "changed":
$color = "blue";
break;
case "repaired":
$color = "blue";
break;
default:
$color="";
}
echo "<li style=\"color: $color\">$message</li>";
}
}
}
/**
* Returns the SELECT clauses ready for inserting into a query.
* @param array $select Select columns
* @param boolean $distinct Distinct select?
* @return string
*/
public function sqlSelectToString($select, $distinct = false) {
$clauses = array();
foreach($select as $alias => $field) {
// Don't include redundant aliases.
if($alias === $field || preg_match('/"' . preg_quote($alias) . '"$/', $field)) $clauses[] = $field;
else $clauses[] = "$field AS \"$alias\"";
}
$text = 'SELECT ';
if($distinct) $text .= 'DISTINCT ';
return $text .= implode(', ', $clauses);
}
/**
* Return the FROM clause ready for inserting into a query.
* @return string
*/
public function sqlFromToString($from) {
return ' FROM ' . implode(' ', $from);
}
/**
* Returns the WHERE clauses ready for inserting into a query.
* @return string
*/
public function sqlWhereToString($where, $connective) {
return ' WHERE (' . implode(") {$connective} (" , $where) . ')';
}
/**
* Returns the ORDER BY clauses ready for inserting into a query.
* @return string
*/
public function sqlOrderByToString($orderby) {
$statements = array();
foreach($orderby as $clause => $dir) {
$statements[] = trim($clause . ' ' . $dir);
}
return ' ORDER BY ' . implode(', ', $statements);
}
/**
* Returns the GROUP BY clauses ready for inserting into a query.
* @return string
*/
public function sqlGroupByToString($groupby) {
return ' GROUP BY ' . implode(', ', $groupby);
}
/**
* Returns the HAVING clauses ready for inserting into a query.
* @return string
*/
public function sqlHavingToString($having) {
return ' HAVING ( ' . implode(' ) AND ( ', $having) . ')';
}
/**
* Return the LIMIT clause ready for inserting into a query.
* @return string
*/
public function sqlLimitToString($limit) {
$clause = '';
// Pass limit as array or SQL string value
if(is_array($limit)) {
if(!array_key_exists('limit', $limit)) {
throw new InvalidArgumentException('Database::sqlLimitToString(): Wrong format for $limit: '
. var_export($limit, true));
}
if(isset($limit['start']) && is_numeric($limit['start']) && isset($limit['limit'])
&& is_numeric($limit['limit'])) {
$combinedLimit = $limit['start'] ? "$limit[limit] OFFSET $limit[start]" : "$limit[limit]";
} elseif(isset($limit['limit']) && is_numeric($limit['limit'])) {
$combinedLimit = (int) $limit['limit'];
} else {
$combinedLimit = false;
}
if(!empty($combinedLimit)) $clause .= ' LIMIT ' . $combinedLimit;
} else {
$clause .= ' LIMIT ' . $limit;
}
return $clause;
}
/**
* Convert a SQLQuery object into a SQL statement
* @param $query SQLQuery
*/
public function sqlQueryToString(SQLQuery $query) {
if($query->getDelete()) {
$text = 'DELETE ';
} else {
$text = $this->sqlSelectToString($query->getSelect(), $query->getDistinct());
}
if($query->getFrom()) $text .= $this->sqlFromToString($query->getFrom());
if($query->getWhere()) $text .= $this->sqlWhereToString($query->getWhere(), $query->getConnective());
// these clauses only make sense in SELECT queries, not DELETE
if(!$query->getDelete()) {
if($query->getGroupBy()) $text .= $this->sqlGroupByToString($query->getGroupBy());
if($query->getHaving()) $text .= $this->sqlHavingToString($query->getHaving());
if($query->getOrderBy()) $text .= $this->sqlOrderByToString($query->getOrderBy());
if($query->getLimit()) $text .= $this->sqlLimitToString($query->getLimit());
}
return $text;
}
/**
* Wrap a string into DB-specific quotes. MySQL, PostgreSQL and SQLite3 only need single quotes around the string.
* MSSQL will overload this and include it's own N prefix to mark the string as unicode, so characters like macrons
* are saved correctly.
*
* @param string $string String to be prepared for database query
* @return string Prepared string
*/
public function prepStringForDB($string) {
return "'" . Convert::raw2sql($string) . "'";
}
/**
* function to return an SQL datetime expression that can be used with the adapter in use
* used for querying a datetime in a certain format
* @param string $date to be formated, can be either 'now', literal datetime like '1973-10-14 10:30:00' or
* field name, e.g. '"SiteTree"."Created"'
* @param string $format to be used, supported specifiers:
* %Y = Year (four digits)
* %m = Month (01..12)
* %d = Day (01..31)
* %H = Hour (00..23)
* %i = Minutes (00..59)
* %s = Seconds (00..59)
* %U = unix timestamp, can only be used on it's own
* @return string SQL datetime expression to query for a formatted datetime
*/
abstract public function formattedDatetimeClause($date, $format);
/**
* function to return an SQL datetime expression that can be used with the adapter in use
* used for querying a datetime addition
* @param string $date, can be either 'now', literal datetime like '1973-10-14 10:30:00' or field name,
* e.g. '"SiteTree"."Created"'
* @param string $interval to be added, use the format [sign][integer] [qualifier], e.g. -1 Day, +15 minutes,
* +1 YEAR
* supported qualifiers:
* - years
* - months
* - days
* - hours
* - minutes
* - seconds
* This includes the singular forms as well
* @return string SQL datetime expression to query for a datetime (YYYY-MM-DD hh:mm:ss) which is the result of
* the addition
*/
abstract public function datetimeIntervalClause($date, $interval);
/**
* function to return an SQL datetime expression that can be used with the adapter in use
* used for querying a datetime substraction
* @param string $date1, can be either 'now', literal datetime like '1973-10-14 10:30:00' or field name
* e.g. '"SiteTree"."Created"'
* @param string $date2 to be substracted of $date1, can be either 'now', literal datetime
* like '1973-10-14 10:30:00' or field name, e.g. '"SiteTree"."Created"'
* @return string SQL datetime expression to query for the interval between $date1 and $date2 in seconds which
* is the result of the substraction
*/
abstract public function datetimeDifferenceClause($date1, $date2);
/**
* Can the database override timezone as a connection setting,
* or does it use the system timezone exclusively?
*
* @return Boolean
*/
abstract public function supportsTimezoneOverride();
/*
* Does this database support transactions?
*
* @return boolean
*/
abstract public function supportsTransactions();
/*
* Start a prepared transaction
* See http://developer.postgresql.org/pgdocs/postgres/sql-set-transaction.html for details on
* transaction isolation options
*/
abstract public function transactionStart($transaction_mode=false, $session_characteristics=false);
/*
* Create a savepoint that you can jump back to if you encounter problems
*/
abstract public function transactionSavepoint($savepoint);
/*
* Rollback or revert to a savepoint if your queries encounter problems
* If you encounter a problem at any point during a transaction, you may
* need to rollback that particular query, or return to a savepoint
*/
abstract public function transactionRollback($savepoint=false);
/*
* Commit everything inside this transaction so far
*/
abstract public function transactionEnd();
/**
* Determines if the used database supports application-level locks,
* which is different from table- or row-level locking.
* See {@link getLock()} for details.
*
* @return boolean
*/
public function supportsLocks() {
return false;
}
/**
* Returns if the lock is available.
* See {@link supportsLocks()} to check if locking is generally supported.
*
* @return Boolean
*/
public function canLock($name) {
return false;
}
/**
* Sets an application-level lock so that no two processes can run at the same time,
* also called a "cooperative advisory lock".
*
* Return FALSE if acquiring the lock fails; otherwise return TRUE, if lock was acquired successfully.
* Lock is automatically released if connection to the database is broken (either normally or abnormally),
* making it less prone to deadlocks than session- or file-based locks.
* Should be accompanied by a {@link releaseLock()} call after the logic requiring the lock has completed.
* Can be called multiple times, in which case locks "stack" (PostgreSQL, SQL Server),
* or auto-releases the previous lock (MySQL).
*
* Note that this might trigger the database to wait for the lock to be released, delaying further execution.
*
* @param String
* @param Int Timeout in seconds
* @return Boolean
*/
public function getLock($name, $timeout = 5) {
return false;
}
/**
* Remove an application-level lock file to allow another process to run
* (if the execution aborts (e.g. due to an error) all locks are automatically released).
*
* @param String
* @return Boolean
*/
public function releaseLock($name) {
return false;
}
}
/**
* Abstract query-result class.
* Once again, this should be subclassed by an actual database implementation. It will only
* ever be constructed by a subclass of SS_Database. The result of a database query - an iteratable object
* that's returned by DB::SS_Query
*
* Primarily, the SS_Query class takes care of the iterator plumbing, letting the subclasses focusing
* on providing the specific data-access methods that are required: {@link nextRecord()}, {@link numRecords()}
* and {@link seek()}
* @package framework
* @subpackage model
*/
abstract class SS_Query implements Iterator {
/**
* The current record in the interator.
* @var array
*/
private $currentRecord = null;
/**
* The number of the current row in the interator.
* @var int
*/
private $rowNum = -1;
/**
* Flag to keep track of whether iteration has begun, to prevent unnecessary seeks
*/
private $queryHasBegun = false;
/**
* Return an array containing all the values from a specific column. If no column is set, then the first will be
* returned
*
* @param string $column
* @return array
*/
public function column($column = null) {
$result = array();
while($record = $this->next()) {
if($column) $result[] = $record[$column];
else $result[] = $record[key($record)];
}
return $result;
}
/**
* Return an array containing all values in the leftmost column, where the keys are the
* same as the values.
* @return array
*/
public function keyedColumn() {
$column = array();
foreach($this as $record) {
$val = $record[key($record)];
$column[$val] = $val;
}
return $column;
}
/**
* Return a map from the first column to the second column.
* @return array
*/
public function map() {
$column = array();
foreach($this as $record) {
$key = reset($record);
$val = next($record);
$column[$key] = $val;
}
return $column;
}
/**
* Returns the next record in the iterator.
* @return array
*/
public function record() {
return $this->next();
}
/**
* Returns the first column of the first record.
* @return string
*/
public function value() {
$record = $this->next();
if($record) return $record[key($record)];
}
/**
* Return an HTML table containing the full result-set
*/
public function table() {
$first = true;
$result = "<table>\n";
foreach($this as $record) {
if($first) {
$result .= "<tr>";
foreach($record as $k => $v) {
$result .= "<th>" . Convert::raw2xml($k) . "</th> ";
}
$result .= "</tr> \n";
}
$result .= "<tr>";
foreach($record as $k => $v) {
$result .= "<td>" . Convert::raw2xml($v) . "</td> ";
}
$result .= "</tr> \n";
$first = false;
}
$result .= "</table>\n";
if($first) return "No records found";
return $result;
}
/**
* Iterator function implementation. Rewind the iterator to the first item and return it.
* Makes use of {@link seek()} and {@link numRecords()}, takes care of the plumbing.
* @return array
*/
public function rewind() {
if($this->queryHasBegun && $this->numRecords() > 0) {
$this->queryHasBegun = false;
return $this->seek(0);
}
}
/**
* Iterator function implementation. Return the current item of the iterator.
* @return array
*/
public function current() {
if(!$this->currentRecord) {
return $this->next();
} else {
return $this->currentRecord;
}
}
/**
* Iterator function implementation. Return the first item of this iterator.
* @return array
*/
public function first() {
$this->rewind();
return $this->current();
}
/**
* Iterator function implementation. Return the row number of the current item.
* @return int
*/
public function key() {
return $this->rowNum;
}
/**
* Iterator function implementation. Return the next record in the iterator.
* Makes use of {@link nextRecord()}, takes care of the plumbing.
* @return array
*/
public function next() {
$this->queryHasBegun = true;
$this->currentRecord = $this->nextRecord();
$this->rowNum++;
return $this->currentRecord;
}
/**
* Iterator function implementation. Check if the iterator is pointing to a valid item.
* @return boolean
*/
public function valid() {
if(!$this->queryHasBegun) $this->next();
return $this->currentRecord !== false;
}
/**
* Return the next record in the query result.
* @return array
*/
abstract public function nextRecord();
/**
* Return the total number of items in the query result.
* @return int
*/
abstract public function numRecords();
/**
* Go to a specific row number in the query result and return the record.
* @param int $rowNum Tow number to go to.
* @return array
*/
abstract public function seek($rowNum);
}