add identity and lock

[m6w6/pq-gateway] / lib / pq / Gateway / Table / Identity.php

diff --git a/lib/pq/Gateway/Table/Identity.php b/lib/pq/Gateway/Table/Identity.php
new file mode 100644 (file)
index 0000000..fcc133b
--- /dev/null
+++ b/lib/pq/Gateway/Table/Identity.php
@@ -0,0 +1,70 @@
+<?php
+
+namespace pq\Gateway\Table;
+
+use \pq\Gateway\Table;
+
+const IDENTITY_SQL = <<<SQL
+select
+ a.attname as column
+from  pg_class     c
+ join pg_index     i  on c.oid    = i.indrelid
+ join pg_attribute a  on c.oid    = a.attrelid
+where 
+     c.relname = \$1
+ and a.attnum  = any(i.indkey)
+ and i.indisprimary
+order by 
+ a.attnum
+SQL;
+
+/**
+ * A primary key implementation
+ */
+class Identity implements \Countable, \IteratorAggregate
+{
+       /**
+        * @var array
+        */
+       protected $columns = array();
+       
+       /**
+        * @param \pq\Gateway\Table $table
+        */
+       function __construct(Table $table) {
+               $cache = $table->getMetadataCache();
+               if (!($this->columns = $cache->get("$table#identity"))) {
+                       $table->getQueryExecutor()->execute(
+                               new \pq\Query\Writer(IDENTITY_SQL, array($table->getName())), 
+                               function($result) use($table, $cache) {
+                                       $this->columns = array_map("current", $result->fetchAll(\pq\Result::FETCH_ARRAY));
+                                       $cache->set("$table#identity", $this->columns);
+                               }
+                       );
+               }
+       }
+       
+       /**
+        * @implements \Countable
+        * @return int
+        */
+       function count() {
+               return count($this->columns);
+       }
+       
+       /**
+        * @implements \IteratorAggregate
+        * @return \ArrayIterator
+        */
+       function getIterator() {
+               return new \ArrayIterator($this->columns);
+       }
+       
+       /**
+        * Get the column names which the primary key contains
+        * @return array
+        */
+       function getColumns() {
+               return $this->columns;
+       }
+}