From fb76304b3bc760d6d035e4478dfbf93a878f8e7d Mon Sep 17 00:00:00 2001
From: skodak <skodak>
Date: Mon, 27 Oct 2008 20:21:04 +0000
Subject: [PATCH] MDL-17020 dml: native pgsql driver - implementation and
 unittests of transactions

---
 lib/dml/moodle_database.php              |  6 +--
 lib/dml/pgsql_native_moodle_database.php | 43 ++++++++++++++++
 lib/dml/simpletest/testdml.php           | 63 ++++++++++++++++++++++++
 3 files changed, 109 insertions(+), 3 deletions(-)

diff --git a/lib/dml/moodle_database.php b/lib/dml/moodle_database.php
index 2ac78095105..cedb15eacef 100644
--- a/lib/dml/moodle_database.php
+++ b/lib/dml/moodle_database.php
@@ -1543,21 +1543,21 @@ abstract class moodle_database {
      * this is _very_ useful for massive updates
      */
     public function begin_sql() {
-        return true;
+        return false;
     }
 
     /**
      * on DBs that support it, commit the transaction
      */
     public function commit_sql() {
-        return true;
+        return false;
     }
 
     /**
      * on DBs that support it, rollback the transaction
      */
     public function rollback_sql() {
-        return true;
+        return false;
     }
 
 /// performance and logging
diff --git a/lib/dml/pgsql_native_moodle_database.php b/lib/dml/pgsql_native_moodle_database.php
index c76e17ce487..ca78d839cb5 100644
--- a/lib/dml/pgsql_native_moodle_database.php
+++ b/lib/dml/pgsql_native_moodle_database.php
@@ -1036,4 +1036,47 @@ class pgsql_native_moodle_database extends moodle_database {
         return $positivematch ? '~*' : '!~*';
     }
 
+/// transactions
+    /**
+     * on DBs that support it, switch to transaction mode and begin a transaction
+     * you'll need to ensure you call commit_sql() or your changes *will* be lost.
+     *
+     * this is _very_ useful for massive updates
+     */
+    public function begin_sql() {
+        $sql = "BEGIN ISOLATION LEVEL READ COMMITTED";
+        $result = pg_query($this->pgsql, $sql);
+        if ($result === false) {
+            return false;
+        }
+        pg_free_result($result);
+        return true;
+    }
+
+    /**
+     * on DBs that support it, commit the transaction
+     */
+    public function commit_sql() {
+        $sql = "COMMIT";
+        $result = pg_query($this->pgsql, $sql);
+        if ($result === false) {
+            return false;
+        }
+        pg_free_result($result);
+        return true;
+    }
+
+    /**
+     * on DBs that support it, rollback the transaction
+     */
+    public function rollback_sql() {
+        $sql = "ROLLBACK";
+        $result = pg_query($this->pgsql, $sql);
+        if ($result === false) {
+            return false;
+        }
+        pg_free_result($result);
+        return true;
+    }
+
 }
diff --git a/lib/dml/simpletest/testdml.php b/lib/dml/simpletest/testdml.php
index 01a19420bda..3be5bad67c9 100755
--- a/lib/dml/simpletest/testdml.php
+++ b/lib/dml/simpletest/testdml.php
@@ -1394,6 +1394,69 @@ class dml_test extends UnitTestCase {
         $this->assertEqual($DB->get_field_sql(
                 "SELECT " . $DB->sql_position("'Oracle'", "'Moodle'") . $DB->sql_null_from_clause()), 0);
     }
+
+    function test_begin_sql() {
+        $DB = $this->tdb;
+        $dbman = $DB->get_manager();
+
+        $table = $this->get_test_table($dbman, "testtable");
+        $table->add_field('id', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, XMLDB_SEQUENCE, null, null, null);
+        $table->add_field('course', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null, null, '0');
+        $table->add_key('primary', XMLDB_KEY_PRIMARY, array('id'));
+        $dbman->create_table($table);
+        $this->tables[$table->getName()] = $table;
+
+        $active = $DB->begin_sql();
+        if ($active) {
+            // test only if driver supports transactions
+            $data = (object)array('course'=>3);
+            $DB->insert_record('testtable', $data);
+            $this->assertEqual(1, $DB->count_records('testtable'));
+            $DB->commit_sql();
+        }
+    }
+
+    function test_commit_sql() {
+        $DB = $this->tdb;
+        $dbman = $DB->get_manager();
+
+        $table = $this->get_test_table($dbman, "testtable");
+        $table->add_field('id', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, XMLDB_SEQUENCE, null, null, null);
+        $table->add_field('course', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null, null, '0');
+        $table->add_key('primary', XMLDB_KEY_PRIMARY, array('id'));
+        $dbman->create_table($table);
+        $this->tables[$table->getName()] = $table;
+
+        $active = $DB->begin_sql();
+        if ($active) {
+            // test only if driver supports transactions
+            $data = (object)array('course'=>3);
+            $DB->insert_record('testtable', $data);
+            $DB->commit_sql();
+            $this->assertEqual(1, $DB->count_records('testtable'));
+        }
+    }
+
+    function test_rollback_sql() {
+        $DB = $this->tdb;
+        $dbman = $DB->get_manager();
+
+        $table = $this->get_test_table($dbman, "testtable");
+        $table->add_field('id', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, XMLDB_SEQUENCE, null, null, null);
+        $table->add_field('course', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null, null, '0');
+        $table->add_key('primary', XMLDB_KEY_PRIMARY, array('id'));
+        $dbman->create_table($table);
+        $this->tables[$table->getName()] = $table;
+
+        $active = $DB->begin_sql();
+        if ($active) {
+            // test only if driver supports transactions
+            $data = (object)array('course'=>3);
+            $DB->insert_record('testtable', $data);
+            $DB->rollback_sql();
+            $this->assertEqual(0, $DB->count_records('testtable'));
+        }
+    }
 }
 
 /**