<?php
/**
* @package DATA_MySQL5
*/
/**
* This class is the abstraction of a MySQL5 table implementing the
* array access and iteration behavior.
*
* Row offset may be indicated by either an int or a string.
* Each access has different meanings:
*
* int: the n-th row as fetched through a simple select query. This access is
* read only.
*
* string: either the primary key value or, if the table has an auto-increment
* primary key and there is only one unique index, the unique field value.
*
* Example:
* <code>
* // loop through a table
* foreach ($DB['table'] as $rowNumber => $row) {
* ...
* }
*
* // check for row existence
* if (isset($DB['table'][$rowIndex])) {
* ...
* }
*
* // get the first row in table
* $readOnlyRow = $DB['table'][0];
* // get the row with pk or an uniquely indexed field equal to 'name'
* $row = $DB['table']['name'];
*
* // insert a row
* $DB['table'][] = array(...);
* // update a row
* $DB['table']['name'] = $row;
*
* // delete a row
* unset($DB['table']['name']);
* </code>
*/
class DATA_MySQL5_Table implements ArrayAccess, Countable, IteratorAggregate {
/**
* Stores table name on construction for future operations.
* @var string
*/
protected $table;
/**
* Strategy for mapping an array offset to rows in the table.
* @var DATA_MySQL5_AssociativeIndexingStrategy
*/
protected $indexingStrategy;
/**
* Disables inboxing in this object.
* @var bool
*/
protected $inboxingDisabled;
/**
* Constructor.
*
* @param string $table The table name.
* @param DATA_MySQL5_AssociativeIndexingStrategy $indexingStrategy Indexing strategy. Optional, defaults to {@link DATA_MySQL5_DefaultIndexingStrategy}.
*/
public function __construct($table, $indexingStrategy = null) {
$this->table = $table;
if ($indexingStrategy === null) {
$indexingStrategy = new DATA_MySQL5_DefaultIndexingStrategy($table);
}
$this->indexingStrategy = $indexingStrategy;
$this->inboxingDisabled = false;
}
/**
* isset(..) handler. Indicates if row exists.
*
* Throws {@link DATA_PrimaryKeyNeeded}, {@link DATA_PrimaryKeyTooLarge}.
*
* @param mixed $row The row offset.
* @return bool True if row exists, false otherwise.
*/
public function offsetExists($row) {
$row = $this->inboxRowOffset($row);
if (is_int($row)) {
return 0 <= $row && $row < $this->count();
} else {
$sql = $this->buildSelectRowQuery($row, "COUNT(*)");
$query = DATA_MySQL5_Access::query($sql);
return DATA_MySQL5_Access::result($query, 0) > 0;
}
}
/**
* [..] handler. Returns a row object corresponding to the row requested.
*
* Throws {@link DATA_PrimaryKeyNeeded}, {@link DATA_PrimaryKeyTooLarge},
* {@link DATA_RowDoesntExist}.
*
* @param mixed $row The row offset.
* @return DATA_MySQL5_Row The row object.
*/
public function offsetGet($row) {
$row = $this->inboxRowOffset($row);
$sql = $this->buildSelectRowQuery($row);
$query = DATA_MySQL5_Access::query($sql);
$data = DATA_MySQL5_Access::fetchAssoc($query);
if (!$data) throw new DATA_RowDoesntExist($this->table, $row);
$row = new DATA_MySQL5_Row($this->table, $data, is_int($row));
if ($this->inboxingDisabled) {
$row = $row->withoutInboxing;
}
return $row;
}
/**
* [..] = handler. Updates or insert a row.
*
* Throws {@link DATA_PrimaryKeyNeeded}, {@link DATA_PrimaryKeyTooLarge}.
*
* @param mixed $row The row offset.
* @param array|ArrayAccess $rowObject The row data.
*/
public function offsetSet($row, $rowObject) {
$row = $this->inboxRowOffset($row);
if (is_int($row)) {
throw new DATA_ReadOnly();
} else {
if ($row !== null && $this->offsetExists($row)) {
DATA_MySQL5_Access::query($this->buildUpdateRowQuery($row, $rowObject));
} else {
DATA_MySQL5_Access::query($this->buildInsertRowQuery($row, $rowObject));
}
if ($rowObject instanceof DATA_MySQL5_Row) {
$rowObject->reattach(DATA_MySQL5_Access::getInsertID());
}
}
}
/**
* unset(..) handler. Deletes a row.
*
* Throws {@link DATA_PrimaryKeyNeeded}, {@link DATA_PrimaryKeyTooLarge}.
*
* @param mixed $row The row offset.
*/
public function offsetUnset($row) {
$row = $this->inboxRowOffset($row);
if (is_int($row)) {
throw new DATA_ReadOnly();
} else {
DATA_MySQL5_Access::query($this->buildDeleteRowQuery($row));
}
}
/**
* count(..) handler. Returns rows count.
*
* @return int How many rows there are on this table.
*/
public function count() {
return (int)DATA_MySQL5_Access::result(DATA_MySQL5_Access::query("SELECT COUNT(*) FROM `{$this->table}`"), 0);
}
/**
* Provides the iterator to be used on a foreach loop.
*
* @return DATA_MySQL5_TableIterator The rows iterator.
*/
public function getIterator() {
return new DATA_MySQL5_TableIterator($this->table);
}
/**
* Builds a select query to fetch one row by the index used for array access.
*
* @param int|DATA_SQLType $row The row offset.
* @param string $select The string to be used as field selection.
* Optional, default to "*".
* @return string SQL query to select the requested row.
*/
protected function buildSelectRowQuery($row, $select = "*") {
$sql = "
SELECT $select
FROM `{$this->table}`
";
if (is_int($row)) {
return $sql . "
LIMIT 1 OFFSET $row
";
} else {
return $sql . $this->buildWhereStatement($row) . "
LIMIT 1
";
}
}
/**
* Builds an update query to modify one row using the data provided on the array access.
*
* @param DATA_SQLType $row The row offset.
* @param array|DATA_MySQL5_Row $rowObject The row data.
* @return string SQL query to update the requested row.
*/
protected function buildUpdateRowQuery($row, $rowObject) {
$sql = "UPDATE `{$this->table}` SET ";
$separator = '';
foreach ($rowObject as $field => $value) {
try {
$value = $this->inboxField($field, $value);
} catch (DATA_SQLTypeConstraintFailed $exception) {
$exception->setTable($this->table);
$exception->setField($field);
throw $exception;
}
$sql .= $separator . "`{$field}` = " . DATA_MySQL5_Access::prepareData($value);
$separator = ', ';
}
$sql .= $this->buildWhereStatement($row);
return $sql;
}
/**
* Builds a delete query to remove one row by the index used for array access.
*
* @param DATA_SQLType $row The row offset.
* @return string SQL query to delete the requested row.
*/
protected function buildDeleteRowQuery($row) {
$sql = "DELETE FROM `{$this->table}` ";
$sql .= $this->buildWhereStatement($row);
return $sql;
}
/**
* Builds a where statement to select one row by the index used for array access.
*
* @param DATA_SQLType $row The row offset.
* @return string SQL where statement to select the requested row.
*/
protected function buildWhereStatement($row) {
$conditions = $this->indexingStrategy->buildWhereConditions($row);
return " WHERE {$conditions} ";
}
/**
* Builds an insert query to add one row using the data provided on the array access.
*
* @param DATA_SQLType $row The row offset.
* @param array|DATA_MySQL5_Row $rowObject The row data.
* @return string SQL query to insert the requested row.
*/
protected function buildInsertRowQuery($row, $rowObject) {
$fieldList = '';
$valueList = '';
$separator = '';
if ($row !== null) {
foreach ($this->indexingStrategy->getAdditionalInsertFields($row) as $field => $value) {
if (isset($rowObject[$field])) continue;
$fieldList .= $separator . "`$field`";
$valueList .= $separator . DATA_MySQL5_Access::prepareData($value);
$separator = ', ';
}
}
foreach ($rowObject as $field => $value) {
try {
$value = $this->inboxField($field, $value);
} catch (DATA_SQLTypeConstraintFailed $exception) {
$exception->setTable($this->table);
$exception->setField($field);
throw $exception;
}
$fieldList .= $separator . "`$field`";
$valueList .= $separator . DATA_MySQL5_Access::prepareData($value);
$separator = ', ';
}
return "INSERT INTO `{$this->table}`($fieldList) VALUES($valueList)";
}
/**
* Returns inboxed version of the row offset provided.
*
* Throws {@link DATA_PrimaryKeyNeeded}, {@link DATA_PrimaryKeyTooLarge}.
*
* @param null|int|string|DATA_SQLType $row The row offset.
* @return DATA_SQLType Inboxed row offset.
*/
protected function inboxRowOffset($row) {
if ($this->inboxingDisabled) return $row;
if (is_int($row) || $row === null) return $row;
return $this->indexingStrategy->inboxRowOffset($row);
}
/**
* Returns inboxed version of the field provided.
*
* Throws {@link DATA_SQLTypeConstraintFailed}.
*
* @param string $field The field name.
* @param null|int|string|DATA_SQLType $value The field value
* @return DATA_SQLType Inboxed field.
*/
protected function inboxField($field, $value) {
if ($this->inboxingDisabled) return $value;
return DATA_MySQL5_Schema::getSQLTypeFactory($this->table, $field)->inbox($value);
}
/**
* Member property overloading.
*
* Watches for properties names byXXXX and maps to the corresponding
* indexing strategy.
*
* withoutInboxing property returns a table object with inboxing of
* mysql types disabled.
*
* @param string $propname Property name.
* @return mixed Property value.
*/
public function __get($propname) {
if (substr($propname, 0, 2) == 'by') {
$field = self::fromUpperCamelCaseToUnderscore(substr($propname, 2));
$keys = DATA_MySQL5_Schema::getPrimaryKey($this->table);
if (count($keys) == 1 && $keys[0] == $field) {
$indexingStrategy = new DATA_MySQL5_PrimaryKeyIndexingStrategy($this->table);
return new DATA_MySQL5_Table($this->table, $indexingStrategy);
}
throw new DATA_NotImplemented('->byXXXX access by any field other than the primary key');
} else if ($propname == 'withoutInboxing') {
$newTable = clone $this;
$newTable->inboxingDisabled = true;
return $newTable;
}
throw new Exception("Undefined property: {$propname}");
}
/**
* Converts from upper camel case notation to underscore lowercase notation.
*
* @param string $name Name in upper camel case.
* @return string Name in underscore lowercase.
*
* @todo Move this function somewhere more appropiate.
*/
protected static function fromUpperCamelCaseToUnderscore($name) {
$name = preg_replace('/(.)([A-Z])/', '$1_$2', $name);
$name = strtolower($name);
return $name;
}
}
?>
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