silverstripe-framework/core/model/Database.php
Will Rossiter 815e9efd94 APICHANGE: removed page comments from core. Please see the github.com account for page comments functionality
git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@114821 467b73ca-7a2a-4603-9d3b-597d59a354a9
2010-12-11 05:43:08 +00:00

983 lines
30 KiB
PHP
Executable File

<?php
/**
* Abstract database connectivity class.
* Sub-classes of this implement the actual database connection libraries
* @package sapphire
* @subpackage model
*/
abstract class SS_Database {
/**
* Connection object to the database.
* @param resource
*/
static $globalConn;
/**
* 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 $errorLevel The level of error reporting to enable for the query
* @return SS_Query
*/
abstract function query($sql, $errorLevel = E_USER_ERROR);
/**
* Get the autogenerated ID from the previous INSERT query.
* @return int
*/
abstract function getGeneratedID($table);
/**
* Check if the connection to the database is active.
* @return boolean
*/
abstract 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 function createDatabase();
/**
* Build the connection string from input
* @param array $parameters The connection details
* @return string $connect The connection string
**/
abstract function getConnect($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 $options An map of additional options. The available keys are as follows:
* - 'MSSQLDatabase'/'MySQLDatabase'/'PostgreSQLDatabase' - database-specific options such as "engine" for MySQL.
* - 'temporary' - If true, then a temporary table will be created
* @return The table name generated. This may be different from the table name, for example with temporary tables.
*/
abstract function createTable($table, $fields = null, $indexes = null, $options = null, $advancedOptions = null);
/**
* Alter a table's schema.
*/
abstract function alterTable($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 $newTableName The new table name.
*/
abstract function renameTable($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 $spec The field specification, eg 'INTEGER NOT NULL'
*/
abstract function createField($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 $newName The new name of the field
*/
abstract function renameField($tableName, $oldName, $newName);
/**
* Get a list of all the fields for the given table.
* Returns a map of field name => field spec.
* @param string $table The table name.
* @return array
*/
protected abstract function fieldList($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
*/
protected abstract function tableList();
/**
* Returns true if the given table exists in the database
*/
abstract function hasTable($tableName);
/**
* Returns the enum values available on the given field
*/
abstract function enumValuesForField($tableName, $fieldName);
/**
* 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;
/**
* 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
*/
function beginSchemaUpdate() {
$this->tableList = array();
$tables = $this->tableList();
foreach($tables as $table) $this->tableList[strtolower($table)] = $table;
$this->indexList = null;
$this->fieldList = null;
$this->schemaUpdateTransaction = array();
}
/**
* Completes a schema-updated transaction, executing all the schema chagnes.
*/
function endSchemaUpdate() {
foreach($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;
}
/**
* Cancels the schema updates requested after a beginSchemaUpdate() call.
*/
function cancelSchemaUpdate() {
$this->schemaUpdateTransaction = null;
}
/**
* Returns true if schema modifications were requested after a beginSchemaUpdate() call.
*/
function doesSchemaNeedUpdating() {
return (bool)$this->schemaUpdateTransaction;
}
// Transactional schema altering functions - they don't do anyhting except for update schemaUpdateTransaction
/**
* @param string $table
* @param string $options
*/
function transCreateTable($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 $options
*/
function transAlterTable($table, $options, $advanced_options) {
$this->transInitTable($table);
$this->schemaUpdateTransaction[$table]['alteredOptions'] = $options;
$this->schemaUpdateTransaction[$table]['advancedOptions'] = $advanced_options;
}
function transCreateField($table, $field, $schema) {
$this->transInitTable($table);
$this->schemaUpdateTransaction[$table]['newFields'][$field] = $schema;
}
function transCreateIndex($table, $index, $schema) {
$this->transInitTable($table);
$this->schemaUpdateTransaction[$table]['newIndexes'][$index] = $schema;
}
function transAlterField($table, $field, $schema) {
$this->transInitTable($table);
$this->schemaUpdateTransaction[$table]['alteredFields'][$field] = $schema;
}
function transAlterIndex($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 $options
*/
function requireTable($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 {
$this->checkAndRepairTable($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 $table The table name.
*/
function dontRequireTable($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 $spec The specification of the index. See requireTable() for more information.
*/
function requireIndex($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))
$spec = ereg_replace(" *, *",",",$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][$index_alt];
}
}
}
//We need to include the name of the fulltext index here so we can trigger a rebuild
//if either the name or the columns have changed.
if(is_array($spec) && isset($spec['type'])){
if($spec['type']=='fulltext'){
$array_spec="({$spec['name']},{$spec['value']})";
}
}
if($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");
}
}
/**
* 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 $spec The field specification. If passed in array syntax, the specific database
* driver takes care of the ALTER TABLE syntax. If passed as a string, its assumed to
* be prepared as a direct SQL framgment ready for insertion into ALTER TABLE. In this case you'll
* need to take care of database abstraction in your DBField subclass.
*/
function requireField($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()) {
$spec = eregi_replace(' *character set [^ ]+( collate [^ ]+)?( |$)','\\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 $fieldName
*/
function dontRequireField($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 $manipulation
*/
function manipulate($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 $array Array where the replacement should happen
*/
static function replace_with_null(&$array) {
$array = ereg_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 $errorLevel The level of the error to throw.
*/
function databaseError($msg, $errorLevel = E_USER_ERROR) {
user_error($msg, $errorLevel);
}
/**
* Enable supression of database messages.
*/
function quiet() {
$this->supressOutput = true;
}
/**
* Show a message about database alteration
*
* @param string message to display
* @param string type one of [created|changed|repaired|obsolete|deleted|error]
*/
function alterationMessage($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>";
}
}
}
/**
* Convert a SQLQuery object into a SQL statement
*/
public function sqlQueryToString(SQLQuery $sqlQuery) {
if (!$sqlQuery->from) return '';
$distinct = $sqlQuery->distinct ? "DISTINCT " : "";
if($sqlQuery->delete) {
$text = "DELETE ";
} else if($sqlQuery->select) {
$text = "SELECT $distinct" . implode(", ", $sqlQuery->select);
}
$text .= " FROM " . implode(" ", $sqlQuery->from);
if($sqlQuery->where) $text .= " WHERE (" . $sqlQuery->getFilter(). ")";
if($sqlQuery->groupby) $text .= " GROUP BY " . implode(", ", $sqlQuery->groupby);
if($sqlQuery->having) $text .= " HAVING ( " . implode(" ) AND ( ", $sqlQuery->having) . " )";
if($sqlQuery->orderby) $text .= " ORDER BY " . $sqlQuery->orderby;
if($sqlQuery->limit) {
$limit = $sqlQuery->limit;
// Pass limit as array or SQL string value
if(is_array($limit)) {
if(!array_key_exists('limit',$limit)) user_error('SQLQuery::limit(): Wrong format for $limit', E_USER_ERROR);
if(isset($limit['start']) && is_numeric($limit['start']) && isset($limit['limit']) && is_numeric($limit['limit'])) {
$combinedLimit = "$limit[limit] OFFSET $limit[start]";
} elseif(isset($limit['limit']) && is_numeric($limit['limit'])) {
$combinedLimit = (int)$limit['limit'];
} else {
$combinedLimit = false;
}
if(!empty($combinedLimit)) $text .= " LIMIT " . $combinedLimit;
} else {
$text .= " LIMIT " . $sqlQuery->limit;
}
}
return $text;
}
/**
* 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 $format to be used, supported specifiers:
* %Y = Year (four digits)
* %m = Month (01..12)
* %d = Day (01..31)
* %H = Hour (00..23)
* %i = Minutes (00..59)
* %s = Seconds (00..59)
* %U = unix timestamp, can only be used on it's own
* @return string SQL datetime expression to query for a formatted datetime
*/
abstract function formattedDatetimeClause($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 $interval to be added, use the format [sign][integer] [qualifier], e.g. -1 Day, +15 minutes, +1 YEAR
* supported qualifiers:
* - years
* - months
* - days
* - hours
* - minutes
* - seconds
* This includes the singular forms as well
* @return string SQL datetime expression to query for a datetime (YYYY-MM-DD hh:mm:ss) which is the result of the addition
*/
abstract function datetimeIntervalClause($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 $date2 in seconds which is the result of the substraction
*/
abstract function datetimeDifferenceClause($date1, $date2);
}
/**
* 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 sapphire
* @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 function nextRecord();
/**
* Return the total number of items in the query result.
* @return int
*/
abstract function numRecords();
/**
* Go to a specific row number in the query result and return the record.
* @param int $rowNum Tow number to go to.
* @return array
*/
abstract function seek($rowNum);
}
?>