Add Table::has_foreign_key method

CHANGELOG.md

@@ -4,7 +4,9 @@ All notable changes to this project will be documented in this file. This projec
 
 ## [unreleased] Unreleased
 
-## [1.1.2] 2022-11-22
+* Feature - Added `Table::has_foreign_key()` method.
+
+## [1.1.2] 2022-11-2
 
 * Tweak - Set the composer's `config.platform.php` to `7.0`.
 

docs/schemas-field.md

@@ -147,17 +147,35 @@ public function after_update() {
 	$table_name = static::table_name( true );
 	$updated    = false;
 
-	if ( $this->exists() && $this->has_index( 'boom' ) ) {
-		$udpated = $wpdb->query( "ALTER TABLE `{$table_name}` ADD UNIQUE( `name` )" );
-	}
+	// Add a UNIQUE constraint on the name column.
+	if ( $this->exists() && ! $this->has_index( 'boom' ) ) {
+		$updated = $wpdb->query( "ALTER TABLE `{$table_name}` ADD UNIQUE( `name` )" );
+
+		if ( $updated ) {
+			$message = "Added UNIQUE constraint to the {$table_name} table on name.";
+		} else {
+			$message = "Failed to add a unique constraint on the {$table_name} table.";
+		}
 
-	if ( $updated ) {
-		$message = "Added UNIQUE constraint to the {$table_name} table on name.";
-	} else {
-		$message = "Failed to add a unique constraint on the {$table_name} table.";
+		$results[ $table_name . '.name' ] = $message;
 	}
 
-	$results[ $table_name . '.name' ] = $message;
+	// Add a FOREIGN KEY constraint on the reseller_id column.
+	if ( $this->exists() && ! $this->has_foreign_key( 'reseller_id' ) ) {
+		$referenced_table = $wpdb->prefix . 'resellers';
+		$updated = $wpdb->query( "ALTER TABLE `{$table_name}`
+			ADD FOREIGN KEY ( `reseller_id` )
+				REFERENCES `$referenced_table` ( `id` )"
+		);
+
+		if ( $updated ) {
+			$message = "Added FOREIGN KEY constraint to the {$table_name} table on reseller_id.";
+		} else {
+			$message = "Failed to add a FOREIGN KEY constraint on the {$table_name} table.";
+		}
+
+		$results[ $table_name . '.reseller_id' ] = $message;
+	}
 
 	return $results;
 }

docs/schemas-table.md

@@ -162,17 +162,35 @@ public function after_update() {
 	$table_name = static::table_name( true );
 	$updated    = false;
 
-	if ( $this->exists() && $this->has_index( 'boom' ) ) {
-		$udpated = $wpdb->query( "ALTER TABLE `{$table_name}` ADD UNIQUE( `name` )" );
-	}
+	// Add a UNIQUE constraint on the name column.
+	if ( $this->exists() && ! $this->has_index( 'boom' ) ) {
+		$updated = $wpdb->query( "ALTER TABLE `{$table_name}` ADD UNIQUE( `name` )" );
+
+		if ( $updated ) {
+			$message = "Added UNIQUE constraint to the {$table_name} table on name.";
+		} else {
+			$message = "Failed to add a unique constraint on the {$table_name} table.";
+		}
 
-	if ( $updated ) {
-		$message = "Added UNIQUE constraint to the {$table_name} table on name.";
-	} else {
-		$message = "Failed to add a unique constraint on the {$table_name} table.";
+		$results[ $table_name . '.name' ] = $message;
 	}
 
-	$results[ $table_name . '.name' ] = $message;
+	// Add a FOREIGN KEY constraint on the reseller_id column.
+	if ( $this->exists() && ! $this->has_foreign_key( 'reseller_id' ) ) {
+		$referenced_table = $wpdb->prefix . 'resellers';
+		$updated = $wpdb->query( "ALTER TABLE `{$table_name}`
+			ADD FOREIGN KEY ( `reseller_id` )
+				REFERENCES `$referenced_table` ( `id` )"
+		);
+
+		if ( $updated ) {
+			$message = "Added FOREIGN KEY constraint to the {$table_name} table on reseller_id.";
+		} else {
+			$message = "Failed to add a FOREIGN KEY constraint on the {$table_name} table.";
+		}
+
+		$results[ $table_name . '.reseller_id' ] = $message;
+	}
 
 	return $results;
 }

src/Schema/Tables/Contracts/Table.php

@@ -531,4 +531,26 @@ public function update() {
 
 		return $results;
 	}
+
+	/**
+	 * Checks if a foreign key exists on a table.
+	 *
+	 * @since TBD
+	 *
+	 * @param string $foreign_key The foreign key to check for.
+	 * @param string|null $table_name The table name to check. Defaults to the current table.
+	 *
+	 * @return bool Whether the foreign key exists on the table.
+	 */
+	public function has_foreign_key( string $foreign_key, string $table_name = null ): bool {
+		$table_name = $table_name ?: static::table_name();
+
+		$count = $this->db::table( $this->db::raw( 'information_schema.statistics' ) )
+		                  ->whereRaw( 'WHERE TABLE_SCHEMA = DATABASE()' )
+		                  ->where( 'TABLE_NAME', $table_name )
+		                  ->where( 'INDEX_NAME', $foreign_key )
+		                  ->count();
+
+		return $count >= 1;
+	}
 }

tests/_support/Traits/Table_Fixtures.php

@@ -163,4 +163,50 @@ protected function get_definition() {
 
 		return $field;
 	}
+
+	public function get_foreign_key_table() {
+		$table = new class extends Table {
+			const SCHEMA_VERSION = '1.0.0';
+
+			protected static $base_table_name = 'foreignkey';
+			protected static $group = 'bork';
+			protected static $schema_slug = 'bork-with-foreignkey';
+			protected static $uid_column = 'id';
+
+			protected function get_definition() {
+				global $wpdb;
+				$table_name      = self::table_name( true );
+				$charset_collate = $wpdb->get_charset_collate();
+
+				return "
+					CREATE TABLE `{$table_name}` (
+						`id` int(11) UNSIGNED NOT NULL,
+						`name` varchar(25) NOT NULL,
+						`simple_id` int(11) UNSIGNED NOT NULL
+					) {$charset_collate};
+				";
+			}
+
+			protected function after_update( array $results ) {
+				if ( $this->has_foreign_key( 'simple_id' ) ) {
+					return $results;
+				}
+
+				global $wpdb;
+				$table_name   = $this->table_name();
+				$simple_table = $wpdb->prefix . 'simple';
+				$updated      = $wpdb->query( "ALTER TABLE $table_name ADD FOREIGN KEY (simple_id) REFERENCES $simple_table(id)" );
+
+				$result = $updated ?
+					'FOREIGN KEY added to ' . $table_name . ' on column simple_id to table ' . $simple_table . ' on column id' :
+					'Failed to add FOREIGN KEY NOT to ' . $table_name . ' on column simple_id to table ' . $simple_table . ' on column id';
+
+				$results[] = $result;
+
+				return $results;
+			}
+		};
+
+		return $table;
+	}
 }

tests/wpunit/Tables/TableTest.php

@@ -9,13 +9,21 @@
 class TableTest extends SchemaTestCase {
 	use Table_Fixtures;
 
+	/**
+	 * @before
+	 */
+	public function drop_tables() {
+		$this->get_simple_table()->drop();
+		$this->get_foreign_key_table()->drop();
+	}
+
 	/**
 	 * Should have index.
 	 *
 	 * @test
 	 */
 	public function should_have_index() {
-		$table   = $this->get_simple_table();
+		$table = $this->get_simple_table();
 
 		Register::table( $table );
 
@@ -28,11 +36,45 @@ public function should_have_index() {
 	 * @test
 	 */
 	public function should_have_fake_index() {
-		$table   = $this->get_simple_table();
+		$table = $this->get_simple_table();
 
 		Register::table( $table );
 
 		$this->assertFalse( $table->has_index( 'bork' ) );
 	}
+
+	/**
+	 * It should not have foreign key
+	 *
+	 * @test
+	 */
+	public function should_not_have_foreign_key() {
+		$simple_table      = $this->get_simple_table();
+		$foreign_key_table = $this->get_foreign_key_table();
+
+		Register::table( $simple_table );
+		Register::table( $foreign_key_table );
+
+		$this->assertFalse( $simple_table->has_foreign_key( 'simple_id' ) );
+		$this->assertFalse( $foreign_key_table->has_foreign_key( 'not_really' ) );
+	}
+
+	/**
+	 * It should have foreign key
+	 *
+	 * @test
+	 */
+	public function should_have_foreign_key() {
+		$simple_table      = $this->get_simple_table();
+		$foreign_key_table = $this->get_foreign_key_table();
+
+		Register::table( $simple_table );
+		Register::table( $foreign_key_table );
+
+		$this->assertFalse( $simple_table->has_foreign_key( 'simple_id' ) );
+		$this->assertFalse( $foreign_key_table->has_foreign_key( 'not_really' ) );
+
+		$this->assertTrue( $foreign_key_table->has_foreign_key( 'simple_id' ) );
+	}
 }