Merge pull request #2201 from MGatner/foreign-key-columns

Foreign key columns

Author: lonnieezell

system/Database/MySQLi/Connection.php

@@ -537,10 +537,14 @@ public function _foreignKeyData(string $table): array
                     SELECT
                         tc.CONSTRAINT_NAME,
                         tc.TABLE_NAME,
-                        rc.REFERENCED_TABLE_NAME
+                        kcu.COLUMN_NAME,
+                        rc.REFERENCED_TABLE_NAME,
+                        kcu.REFERENCED_COLUMN_NAME
                     FROM information_schema.TABLE_CONSTRAINTS AS tc
                     INNER JOIN information_schema.REFERENTIAL_CONSTRAINTS AS rc
                         ON tc.CONSTRAINT_NAME = rc.CONSTRAINT_NAME
+                    INNER JOIN information_schema.KEY_COLUMN_USAGE AS kcu
+                        ON tc.CONSTRAINT_NAME = kcu.CONSTRAINT_NAME
                     WHERE
                         tc.CONSTRAINT_TYPE = ' . $this->escape('FOREIGN KEY') . ' AND
                         tc.TABLE_SCHEMA = ' . $this->escape($this->database) . ' AND
@@ -555,10 +559,12 @@ public function _foreignKeyData(string $table): array
 		$retVal = [];
 		foreach ($query as $row)
 		{
-			$obj                     = new \stdClass();
-			$obj->constraint_name    = $row->CONSTRAINT_NAME;
-			$obj->table_name         = $row->TABLE_NAME;
-			$obj->foreign_table_name = $row->REFERENCED_TABLE_NAME;
+			$obj                      = new \stdClass();
+			$obj->constraint_name     = $row->CONSTRAINT_NAME;
+			$obj->table_name          = $row->TABLE_NAME;
+			$obj->column_name         = $row->COLUMN_NAME;
+			$obj->foreign_table_name  = $row->REFERENCED_TABLE_NAME;
+			$obj->foreign_column_name = $row->REFERENCED_COLUMN_NAME;
 
 			$retVal[] = $obj;
 		}

system/Database/Postgre/Connection.php

@@ -406,11 +406,13 @@ public function _foreignKeyData(string $table): array
 		$retVal = [];
 		foreach ($query as $row)
 		{
-			$obj                     = new \stdClass();
-			$obj->constraint_name    = $row->constraint_name;
-			$obj->table_name         = $row->table_name;
-			$obj->foreign_table_name = $row->foreign_table_name;
-			$retVal[]                = $obj;
+			$obj                      = new \stdClass();
+			$obj->constraint_name     = $row->constraint_name;
+			$obj->table_name          = $row->table_name;
+			$obj->column_name         = $row->column_name;
+			$obj->foreign_table_name  = $row->foreign_table_name;
+			$obj->foreign_column_name = $row->foreign_column_name;
+			$retVal[]                 = $obj;
 		}
 
 		return $retVal;

system/Database/SQLite3/Connection.php

@@ -407,6 +407,7 @@ public function _foreignKeyData(string $table): array
 				$obj->constraint_name    = $row->from . ' to ' . $row->table . '.' . $row->to;
 				$obj->table_name         = $table;
 				$obj->foreign_table_name = $row->table;
+				$obj->sequence           = $row->seq;
 
 				$retVal[] = $obj;
 			}

tests/system/Database/Live/ForgeTest.php

@@ -323,10 +323,13 @@ public function testForeignKey()
 		if ($this->db->DBDriver === 'SQLite3')
 		{
 			$this->assertEquals($foreignKeyData[0]->constraint_name, 'users_id to db_forge_test_users.id');
+			$this->assertEquals($foreignKeyData[0]->sequence, 0);
 		}
 		else
 		{
 			$this->assertEquals($foreignKeyData[0]->constraint_name, $this->db->DBPrefix . 'forge_test_invoices_users_id_foreign');
+			$this->assertEquals($foreignKeyData[0]->column_name, 'users_id');
+			$this->assertEquals($foreignKeyData[0]->foreign_column_name, 'id');
 		}
 		$this->assertEquals($foreignKeyData[0]->table_name, $this->db->DBPrefix . 'forge_test_invoices');
 		$this->assertEquals($foreignKeyData[0]->foreign_table_name, $this->db->DBPrefix . 'forge_test_users');

user_guide_src/source/database/metadata.rst

@@ -163,6 +163,11 @@ Usage example::
 	{
 		echo $key->constraint_name;
 		echo $key->table_name;
+		echo $key->column_name;
 		echo $key->foreign_table_name;
+		echo $key->foreign_column_name;
 	}
 
+The object fields may be unique to the database you are using. For instance, SQLite3 does
+not return data on column names, but has the additional *sequence* field for compound
+foreign key definitions.