fusionpbx/resources/classes/schema.php

<?php

/*
  FusionPBX
  Version: MPL 1.1

  The contents of this file are subject to the Mozilla Public License Version
  1.1 (the "License"); you may not use this file except in compliance with
  the License. You may obtain a copy of the License at
  http://www.mozilla.org/MPL/

  Software distributed under the License is distributed on an "AS IS" basis,
  WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  for the specific language governing rights and limitations under the
  License.

  The Original Code is FusionPBX

  The Initial Developer of the Original Code is
  Mark J Crane <markjcrane@fusionpbx.com>
  Copyright (C) 2013 - 2023
  All Rights Reserved.

  Contributor(s):
  Mark J Crane <markjcrane@fusionpbx.com>
 */

//define the schema class
	class schema {

		//define variables
		private $database;
		public $apps;
		public $db_type;
		public $result;
		public $data_types;

		//class constructor
		public function __construct() {

			//includes files
			require dirname(__DIR__, 2) . "/resources/require.php";

			//connect to the database
			$this->database = database::new();

			//get the list of installed apps from the core and mod directories
			$config_list = glob($_SERVER["DOCUMENT_ROOT"] . PROJECT_PATH . "/*/*/app_config.php");
			$x = 0;
			foreach ($config_list as $config_path) {
				try {
					include($config_path);
				} catch (Exception $e) {
					//echo 'Caught exception: ',  $e->getMessage(), "\n";
				}
				$x++;
			}
			$this->apps = $apps;
		}

		//create the database schema
		public function sql() {
			$sql = '';
			$sql_schema = '';
			foreach ($this->apps as $app) {
				if (isset($app['db']) && count($app['db'])) {
					foreach ($app['db'] as $row) {
						//create the sql string
						$table_name = $row['table']['name'];
						$sql = "CREATE TABLE " . $row['table']['name'] . " (\n";
						$field_count = 0;
						foreach ($row['fields'] as $field) {
							if (!empty($field['deprecated']) and ($field['deprecated'] == "true")) {
								//skip this field
							} else {
								if ($field_count > 0) {
									$sql .= ",\n";
								}
								if (is_array($field['name'])) {
									$sql .= $field['name']['text'] . " ";
								} else {
									$sql .= $field['name'] . " ";
								}
								if (is_array($field['type'])) {
									$sql .= $field['type'][$this->db_type];
								} else {
									$sql .= $field['type'];
								}
								if (isset($field['key']) && isset($field['key']['type']) && ($field['key']['type'] == "primary")) {
									$sql .= " PRIMARY KEY";
								}
								if (isset($field['key']) && isset($field['key']['type']) && ($field['key']['type'] == "foreign")) {
									if ($this->db_type == "pgsql") {
										//$sql .= " references ".$field['key']['reference']['table']."(".$field['key']['reference']['field'].")";
									}
									if ($this->db_type == "sqlite") {
										//$sql .= " references ".$field['key']['reference']['table']."(".$field['key']['reference']['field'].")";
									}
									if ($this->db_type == "mysql") {
										//$sql .= " references ".$field['key']['reference']['table']."(".$field['key']['reference']['field'].")";
									}
								}
								$field_count++;
							}
						}
						if ($this->db_type == "mysql") {
							$sql .= ") ENGINE=INNODB;";
						} else {
							$sql .= ");";
						}
						$this->result['sql'][] = $sql;
						unset($sql);
					}
				}
			}
		}

		//create the database schema
		public function exec() {
			foreach ($this->result['sql'] as $sql) {
				//start the sql transaction
				$this->database->beginTransaction();
				//execute the sql query
				try {
					$this->database->query($sql);
				} catch (PDOException $error) {
					echo "error: " . $error->getMessage() . " sql: $sql<br/>";
				}
				//complete the transaction
				$this->database->commit();
			}
		}

		//check if a column exists in sqlite
		private function sqlite_column_exists($table_info, $column_name) {
			foreach ($table_info as $key => $row) {
				if ($row['name'] == $column_name) {
					return true;
				}
			}
			return $false;
		}

		//check if a column exists
		public function column_exists($db_name, $table_name, $column_name) {

			if ($this->db_type == "sqlite") {
				$table_info = $this->table_info($db_name, $table_name);
				if ($this->sqlite_column_exists($table_info, $column_name)) {
					return true;
				} else {
					return false;
				}
			}
			if ($this->db_type == "pgsql") {
				$sql = "SELECT attname FROM pg_attribute WHERE attrelid = (SELECT oid FROM pg_class WHERE relname = '$table_name' limit 1) AND attname = '$column_name'; ";
			}
			if ($this->db_type == "mysql") {
				//$sql .= "SELECT * FROM information_schema.COLUMNS where TABLE_SCHEMA = '$db_name' and TABLE_NAME = '$table_name' and COLUMN_NAME = '$column_name' ";
				$sql = "show columns from $table_name where field = '$column_name' ";
			}

			if ($sql) {
				$prep_statement = $this->database->db->prepare($sql);
				$prep_statement->execute();
				$result = $prep_statement->fetchAll(PDO::FETCH_NAMED);
				if (!$result) {
					return false;
				}
				if (count($result) > 0) {
					return true;
				} else {
					return false;
				}
				unset($prep_statement);
			}
		}

		//get the table information
		public function table_info($db_name, $table_name) {
			if (empty($table_name)) {
				return false;
			}
			if ($this->db_type == "sqlite") {
				$sql = "PRAGMA table_info(" . $table_name . ");";
			}
			if ($this->db_type == "pgsql") {
				$sql = "SELECT ordinal_position, ";
				$sql .= "column_name, ";
				$sql .= "data_type, ";
				$sql .= "column_default, ";
				$sql .= "is_nullable, ";
				$sql .= "character_maximum_length, ";
				$sql .= "numeric_precision ";
				$sql .= "FROM information_schema.columns ";
				$sql .= "WHERE table_name = '" . $table_name . "' ";
				$sql .= "and table_catalog = '" . $db_name . "' ";
				$sql .= "ORDER BY ordinal_position; ";
			}
			if ($this->db_type == "mysql") {
				$sql = "describe " . $table_name . ";";
			}
			$prep_statement = $this->database->db->prepare($sql);
			$prep_statement->execute();
			return $prep_statement->fetchAll(PDO::FETCH_ASSOC);
		}

		//database table exists alternate
		private function db_table_exists_alternate($db_type, $table_name) {
			$sql = "select count(*) from $table_name ";
			$result = $this->database->query($sql);
			if ($result > 0) {
				return true; //table exists
			} else {
				return false; //table doesn't exist
			}
		}

		//database table exists
		private function db_table_exists($db_type, $db_name, $table_name) {
			$sql = "";
			if ($db_type == "sqlite") {
				$sql .= "SELECT * FROM sqlite_master WHERE type='table' and name='$table_name' ";
			}
			if ($db_type == "pgsql") {
				$sql .= "select * from pg_tables where schemaname='public' and tablename = '$table_name' ";
			}
			if ($db_type == "mysql") {
				$sql .= "SELECT TABLE_NAME FROM information_schema.tables WHERE table_schema = '$db_name' and TABLE_NAME = '$table_name' ";
			}
			$prep_statement = $this->database->db->prepare(check_sql($sql));
			$prep_statement->execute();
			$result = $prep_statement->fetchAll(PDO::FETCH_NAMED);
			if (count($result) > 0) {
				return true; //table exists
			} else {
				return false; //table doesn't exist
			}
		}

		//database table information
		private function db_table_info($db_name, $db_type, $table_name) {
			if (empty($table_name)) {
				return false;
			}
			if ($db_type == "sqlite") {
				$sql = "PRAGMA table_info(" . $table_name . ");";
			}
			if ($db_type == "pgsql") {
				$sql = "SELECT ordinal_position, ";
				$sql .= "column_name, ";
				$sql .= "data_type, ";
				$sql .= "column_default, ";
				$sql .= "is_nullable, ";
				$sql .= "character_maximum_length, ";
				$sql .= "numeric_precision ";
				$sql .= "FROM information_schema.columns ";
				$sql .= "WHERE table_name = '" . $table_name . "' ";
				$sql .= "and table_catalog = '" . $db_name . "' ";
				$sql .= "ORDER BY ordinal_position; ";
			}
			if ($db_type == "mysql") {
				$sql = "describe " . $table_name . ";";
			}
			$prep_statement = $this->database->db->prepare($sql);
			$prep_statement->execute();
			return $prep_statement->fetchAll(PDO::FETCH_ASSOC);
		}

		//database type
		private function db_data_type($db_type, $table_info, $column_name) {
			if ($db_type == "sqlite") {
				foreach ($table_info as $key => $row) {
					if ($row['name'] == $column_name) {
						return $row['type'];
					}
				}
			}
			if ($db_type == "pgsql") {
				foreach ($table_info as $key => $row) {
					if ($row['column_name'] == $column_name) {
						return $row['data_type'];
					}
				}
			}
			if ($db_type == "mysql") {
				foreach ($table_info as $key => $row) {
					if ($row['Field'] == $column_name) {
						return $row['Type'];
					}
				}
			}
		}

		//sqlite column exists
		private function db_sqlite_column_exists($table_info, $column_name) {
			foreach ($table_info as $key => $row) {
				if ($row['name'] == $column_name) {
					return true;
				}
			}
			return $false;
		}

		//database column exists
		private function db_column_exists($db_type, $db_name, $table_name, $column_name) {

			if ($db_type == "sqlite") {
				$table_info = $this->db_table_info($db_name, $db_type, $table_name);
				if ($this->db_sqlite_column_exists($table_info, $column_name)) {
					return true;
				} else {
					return false;
				}
			}
			if ($db_type == "pgsql") {
				$sql = "SELECT attname FROM pg_attribute WHERE attrelid = (SELECT oid FROM pg_class WHERE relname = '$table_name' limit 1) AND attname = '$column_name'; ";
			}
			if ($db_type == "mysql") {
				//$sql .= "SELECT * FROM information_schema.COLUMNS where TABLE_SCHEMA = '$db_name' and TABLE_NAME = '$table_name' and COLUMN_NAME = '$column_name' ";
				$sql = "show columns from $table_name where field = '$column_name' ";
			}
			if ($sql) {
				$prep_statement = $this->database->db->prepare(check_sql($sql));
				$prep_statement->execute();
				$result = $prep_statement->fetchAll(PDO::FETCH_NAMED);
				if (!empty($result)) {
					return true;
				} else {
					return false;
				}
				unset($prep_statement);
			}
		}

		//database column data type
		private function db_column_data_type($db_type, $db_name, $table_name, $column_name) {
			$table_info = $this->db_table_info($db_name, $db_type, $table_name);
			return $this->db_data_type($db_type, $table_info, $column_name);
		}

		//database create table
		public function db_create_table($apps, $db_type, $table) {
			if (empty($apps)) {
				return false;
			}
			if (is_array($apps)) {
				foreach ($apps as $x => $app) {
					if (!empty($app['db']) && is_array($app['db'])) {
						foreach ($app['db'] as $y => $row) {
							if (!empty($row['table']['name']) && is_array($row['table']['name'])) {
								$table_name = $row['table']['name']['text'];
							} else {
								$table_name = $row['table']['name'];
							}
							if ($table_name == $table) {
								$sql = "CREATE TABLE " . $table_name . " (\n";
								(int) $field_count = 0;
								if (!empty($row['fields']) && is_array($row['fields'])) {
									foreach ($row['fields'] as $field) {
										if (!empty($field['deprecated']) && $field['deprecated'] == "true") {
											//skip this row
										} else {
											if ($field_count > 0) {
												$sql .= ",\n";
											}
											if (!empty($field['name']) && is_array($field['name'])) {
												$sql .= $field['name']['text'] . " ";
											} else {
												$sql .= $field['name'] . " ";
											}
											if (!empty($field['type']) && is_array($field['type'])) {
												$sql .= $field['type'][$db_type];
											} else {
												$sql .= $field['type'];
											}
											if (!empty($field['key']['type']) && $field['key']['type'] == "primary") {
												$sql .= " PRIMARY KEY";
											}
											$field_count++;
										}
									}
								}
								$sql .= ");\n";
								return $sql;
							}
						}
					}
				}
			}
		}

		//database insert
		private function db_insert_into($apps, $db_type, $table) {
			global $db_name;
			foreach ($apps as $x => $app) {
				foreach ($app['db'] as $y => $row) {
					if ($row['table']['name'] == $table) {
						$sql = "INSERT INTO " . $row['table']['name'] . " (";
						$field_count = 0;
						foreach ($row['fields'] as $field) {
							if (!empty($field['deprecated']) && $field['deprecated'] == "true") {
								//skip this field
							} else {
								if ($field_count > 0) {
									$sql .= ",";
								}
								if (is_array($field['name'])) {
									$sql .= $field['name']['text'];
								} else {
									$sql .= $field['name'];
								}
								$field_count++;
							}
						}
						$sql .= ")\n";
						$sql .= "SELECT ";
						$field_count = 0;
						foreach ($row['fields'] as $field) {
							if (!empty($field['deprecated']) && $field['deprecated'] == "true") {
								//skip this field
							} else {
								if ($field_count > 0) {
									$sql .= ",";
								}
								if (is_array($field['name'])) {
									if ($field['exists'] == "false") {
										if (is_array($field['name']['deprecated'])) {
											$found = false;
											foreach ($field['name']['deprecated'] as $row) {
												if ($this->db_column_exists($db_type, $db_name, 'tmp_' . $table, $row)) {
													$sql .= $row;
													$found = true;
													break;
												}
											}
											if (!$found) {
												$sql .= "''";
											}
										} else {
											if ($this->db_column_exists($db_type, $db_name, 'tmp_' . $table, $field['name']['deprecated'])) {
												$sql .= $field['name']['deprecated'];
											} else {
												$sql .= "''";
											}
										}
									} else {
										$sql .= $field['name']['text'];
									}
								} else {
									$sql .= $field['name'];
								}
								$field_count++;
							}
						}
						$sql .= " FROM tmp_" . $table . ";\n";
						return $sql;
					}
				}
			}
		}

		//datatase schema
		public function schema($format = '') {

			//set the global variable
			global $text, $output_format;

			if ($format == '') {
				$format = $output_format;
			}

			//get the db variables
			//$config = new config;
			//$config_exists = $config->exists();
			//$config_path = $config->find();
			//$config->get();
			//$db_type = $config->db_type;
			//$db_name = $config->db_name;
			//$db_username = $config->db_username;
			//$db_password = $config->db_password;
			//$db_host = $config->db_host;
			//$db_path = $config->db_path;
			//$db_port = $config->db_port;
			//includes files
			require dirname(__DIR__, 2) . "/resources/require.php";

			//add multi-lingual support
			if (!isset($text)) {
				$language = new text;
				$text = $language->get(null, 'core/upgrade');
			}

			//PHP PDO check if table or column exists
			//check if table exists
			// SELECT * FROM sqlite_master WHERE type='table' AND name='v_cdr'
			//check if column exists
			// SELECT * FROM sqlite_master WHERE type='table' AND name='v_cdr' AND sql LIKE '%caller_id_name TEXT,%'
			//aditional information
			// http://www.sqlite.org/faq.html#q9
			//postgresql
			//list all tables in the database
			// SELECT table_name FROM pg_tables WHERE schemaname='public';
			//check if table exists
			// SELECT * FROM pg_tables WHERE schemaname='public' AND table_name = 'v_groups'
			//check if column exists
			// SELECT attname FROM pg_attribute WHERE attrelid = (SELECT oid FROM pg_class WHERE relname = 'v_cdr') AND attname = 'caller_id_name';
			//mysql
			//list all tables in the database
			// SELECT TABLE_NAME FROM information_schema.tables WHERE table_schema = 'fusionpbx'
			//check if table exists
			// SELECT TABLE_NAME FROM information_schema.tables WHERE table_schema = 'fusionpbx' AND TABLE_NAME = 'v_groups'
			//check if column exists
			// SELECT * FROM information_schema.COLUMNS where TABLE_SCHEMA = 'fusionpbx' AND TABLE_NAME = 'v_cdr' AND COLUMN_NAME = 'context'
			//oracle
			//check if table exists
			// SELECT TABLE_NAME FROM ALL_TABLES
			//update the app db array add exists true or false
			$sql = '';
			foreach ($this->apps as $x => $app) {
				if (isset($app['db'])) {
					foreach ($app['db'] as $y => $row) {
						if (isset($row['table']['name'])) {
							if (is_array($row['table']['name'])) {
								$table_name = $row['table']['name']['text'];
							} else {
								$table_name = $row['table']['name'];
							}
						} else {
							//old array syntax
							if (is_array($row['table'])) {
								$table_name = $row['table']['text'];
							} else {
								$table_name = $row['table'];
							}
						}
						if (!empty($table_name)) {

							//check if the table exists
							if ($this->db_table_exists($db_type, $db_name, $table_name)) {
								$this->apps[$x]['db'][$y]['exists'] = 'true';
							} else {
								$this->apps[$x]['db'][$y]['exists'] = 'false';
							}
							//check if the column exists
							foreach ($row['fields'] as $z => $field) {
								if (!empty($field['deprecated']) && $field['deprecated'] == "true") {
									//skip this field
								} else {
									if (is_array($field['name'])) {
										$field_name = $field['name']['text'];
									} else {
										$field_name = $field['name'];
									}
									if (!empty($field_name)) {
										if ($this->db_column_exists($db_type, $db_name, $table_name, $field_name)) {
											//found
											$this->apps[$x]['db'][$y]['fields'][$z]['exists'] = 'true';
										} else {
											//not found
											$this->apps[$x]['db'][$y]['fields'][$z]['exists'] = 'false';
										}
									}
									unset($field_name);
								}
							}
							unset($table_name);
						}
					}
				}
			}

			//prepare the variables
			$sql_update = '';

			//add missing tables and fields
			foreach ($this->apps as $x => $app) {
				if (isset($app['db'])) {
					foreach ($app['db'] as $y => $row) {
						if (is_array($row['table']['name'])) {
							$table_name = $row['table']['name']['text'];
							if ($this->db_table_exists($db_type, $db_name, $row['table']['name']['deprecated'])) {
								$row['exists'] = "false"; //testing
								if ($db_type == "pgsql") {
									$sql_update .= "ALTER TABLE " . $row['table']['name']['deprecated'] . " RENAME TO " . $row['table']['name']['text'] . ";\n";
								}
								if ($db_type == "mysql") {
									$sql_update .= "RENAME TABLE " . $row['table']['name']['deprecated'] . " TO " . $row['table']['name']['text'] . ";\n";
								}
								if ($db_type == "sqlite") {
									$sql_update .= "ALTER TABLE " . $row['table']['name']['deprecated'] . " RENAME TO " . $row['table']['name']['text'] . ";\n";
								}
							} else {
								if ($this->db_table_exists($db_type, $db_name, $row['table']['name']['text'])) {
									$row['exists'] = "true";
								} else {
									$row['exists'] = "false";
									$sql_update .= $this->db_create_table($this->apps, $db_type, $row['table']['name']['text']);
								}
							}
						} else {
							if ($this->db_table_exists($db_type, $db_name, $row['table']['name'])) {
								$row['exists'] = "true";
							} else {
								$row['exists'] = "false";
							}
							$table_name = $row['table']['name'];
						}

						//check if the table exists
						if ($row['exists'] == "true") {
							if (count($row['fields']) > 0) {
								foreach ($row['fields'] as $z => $field) {
									if (!empty($field['deprecated']) && $field['deprecated'] == "true") {
										//skip this field
									} else {
										//get the data type
										if (is_array($field['type'])) {
											$field_type = $field['type'][$db_type];
										} else {
											$field_type = $field['type'];
										}
										//get the field name
										if (is_array($field['name'])) {
											$field_name = $field['name']['text'];
										} else {
											$field_name = $field['name'];
										}

										//check if the field exists
										//	if ($this->db_column_exists($db_type, $db_name, $table_name, $field_name)) {
										//		$field['exists'] = "true";
										//	}
										//	else {
										//		$field['exists'] = "false";
										//	}
										//add or rename fields
										if (isset($field['name']['deprecated']) && $this->db_column_exists($db_type, $db_name, $table_name, $field['name']['deprecated'])) {
											if ($db_type == "pgsql") {
												$sql_update .= "ALTER TABLE " . $table_name . " RENAME COLUMN " . $field['name']['deprecated'] . " to " . $field['name']['text'] . ";\n";
											}
											if ($db_type == "mysql") {
												$field_type = str_replace("AUTO_INCREMENT PRIMARY KEY", "", $field_type);
												$sql_update .= "ALTER TABLE " . $table_name . " CHANGE " . $field['name']['deprecated'] . " " . $field['name']['text'] . " " . $field_type . ";\n";
											}
											if ($db_type == "sqlite") {
												//a change has been made to the field name
												$this->apps[$x]['db'][$y]['rebuild'] = 'true';
											}
										} else {
											//find missing fields and add them
											if ($field['exists'] == "false") {
												$sql_update .= "ALTER TABLE " . $table_name . " ADD " . $field_name . " " . $field_type . ";\n";
											}
										}

										//change the data type if it has been changed
										//if the data type in the app db array is different than the type in the database then change the data type
										if ($this->data_types) {
											$db_field_type = $this->db_column_data_type($db_type, $db_name, $table_name, $field_name);
											$field_type_array = explode("(", $field_type);
											$field_type = $field_type_array[0];
											if (trim($db_field_type) != trim($field_type) && !empty($db_field_type)) {
												if ($db_type == "pgsql") {
													if (strtolower($field_type) == "uuid") {
														$sql_update .= "ALTER TABLE " . $table_name . " ALTER COLUMN " . $field_name . " TYPE uuid USING\n";
														$sql_update .= "CAST(regexp_replace(" . $field_name . ", '([A-Z0-9]{4})([A-Z0-9]{12})', E'\\1-\\2')\n";
														$sql_update .= "AS uuid);\n";
													} else {
														//field type has not changed
														if ($db_field_type == "integer" && strtolower($field_type) == "serial") {

														} else if ($db_field_type == "timestamp without time zone" && strtolower($field_type) == "timestamp") {

														} else if ($db_field_type == "timestamp without time zone" && strtolower($field_type) == "datetime") {

														} else if ($db_field_type == "timestamp with time zone" && strtolower($field_type) == "timestamptz") {

														} else if ($db_field_type == "integer" && strtolower($field_type) == "numeric") {

														} else if ($db_field_type == "character" && strtolower($field_type) == "char") {

														}
														//field type has changed
														else {
															switch ($field_type) {
																case 'numeric': $using = $field_name . "::numeric";
																	break;
																case 'timestamp':
																case 'datetime': $using = $field_name . "::timestamp without time zone";
																	break;
																case 'timestamptz': $using = $field_name . "::timestamp with time zone";
																	break;
																case 'boolean': $using = $field_name . "::boolean";
																	break;
																default: unset($using);
															}
															$sql_update .= "ALTER TABLE " . $table_name . " ALTER COLUMN " . $field_name . " TYPE " . $field_type . " " . ($using ? "USING " . $using : null) . ";\n";
														}
													}
												}
												if ($db_type == "mysql") {
													$type = explode("(", $db_field_type);
													if ($type[0] == $field_type) {
														//do nothing
													} else if ($field_type == "numeric" && $type[0] == "decimal") {
														//do nothing
													} else {
														$sql_update .= "ALTER TABLE " . $table_name . " modify " . $field_name . " " . $field_type . ";\n";
													}
													unset($type);
												}
												if ($db_type == "sqlite") {
													//a change has been made to the field type
													$this->apps[$x]['db'][$y]['rebuild'] = 'true';
												}
											}
										}
									}
								}
							}
						} elseif (!is_array($row['table']['name'])) {
							//create table
							$sql_update .= $this->db_create_table($this->apps, $db_type, $row['table']['name']);
						}
					}
				}
			}
			//rebuild and populate the table
			foreach ($this->apps as $x => $app) {
				if (isset($app['db'])) {
					foreach ($app['db'] as $y => $row) {
						if (is_array($row['table']['name'])) {
							$table_name = $row['table']['name']['text'];
						} else {
							$table_name = $row['table']['name'];
						}
						if (!empty($field['rebuild']) && $row['rebuild'] == "true") {
							if ($db_type == "sqlite") {
								//start the transaction
								//$sql_update .= "BEGIN TRANSACTION;\n";
								//rename the table
								$sql_update .= "ALTER TABLE " . $table_name . " RENAME TO tmp_" . $table_name . ";\n";
								//create the table
								$sql_update .= $this->db_create_table($this->apps, $db_type, $table_name);
								//insert the data into the new table
								$sql_update .= $this->db_insert_into($this->apps, $db_type, $table_name);
								//drop the old table
								$sql_update .= "DROP TABLE tmp_" . $table_name . ";\n";
								//commit the transaction
								//$sql_update .= "COMMIT;\n";
							}
						}
					}
				}
			}

			// initialize response variable
			$response = '';

			//display results as html
			if ($format == "html") {
				//show the database type
				$response .= "<strong>" . $text['header-database_type'] . ": " . $db_type . "</strong><br /><br />";
				//start the table
				$response .= "<table width='100%' border='0' cellpadding='20' cellspacing='0'>\n";
				//show the changes
				if (!empty($sql_update)) {
					$response .= "<tr>\n";
					$response .= "<td class='row_style1' colspan='3'>\n";
					$response .= "<br />\n";
					$response .= "<strong>" . $text['label-sql_changes'] . ":</strong><br />\n";
					$response .= "<pre>\n";
					$response .= $sql_update;
					$response .= "</pre>\n";
					$response .= "<br />\n";
					$response .= "</td>\n";
					$response .= "</tr>\n";
				}
				//list all tables
				$response .= "<tr>\n";
				$response .= "<th>" . $text['label-table'] . "</th>\n";
				$response .= "<th>" . $text['label-exists'] . "</th>\n";
				$response .= "<th>" . $text['label-details'] . "</th>\n";
				$response .= "<tr>\n";
				//build the html while looping through the app db array
				$sql = '';
				foreach ($this->apps as $app) {
					if (isset($app['db'])) {
						foreach ($app['db'] as $row) {
							if (is_array($row['table']['name'])) {
								$table_name = $row['table']['name']['text'];
							} else {
								$table_name = $row['table']['name'];
							}
							$response .= "<tr>\n";

							//check if the table exists
							if ($row['exists'] == "true") {
								$response .= "<td valign='top' class='row_style1'>" . $table_name . "</td>\n";
								$response .= "<td valign='top' class='vncell' style='padding-top: 3px;'>" . $text['option-true'] . "</td>\n";

								if (count($row['fields']) > 0) {
									$response .= "<td class='row_style1'>\n";
									//show the list of columns
									$response .= "<table border='0' cellpadding='10' cellspacing='0'>\n";
									$response .= "<tr>\n";
									$response .= "<th>" . $text['label-name'] . "</th>\n";
									$response .= "<th>" . $text['label-type'] . "</th>\n";
									$response .= "<th>" . $text['label-exists'] . "</th>\n";
									$response .= "</tr>\n";
									foreach ($row['fields'] as $field) {
										if (!empty($field['deprecated']) && $field['deprecated'] == "true") {
											//skip this field
										} else {
											if (is_array($field['name'])) {
												$field_name = $field['name']['text'];
											} else {
												$field_name = $field['name'];
											}
											if (is_array($field['type'])) {
												$field_type = $field['type'][$db_type];
											} else {
												$field_type = $field['type'];
											}
											$response .= "<tr>\n";
											$response .= "<td class='row_style1' width='200'>" . $field_name . "</td>\n";
											$response .= "<td class='row_style1'>" . $field_type . "</td>\n";
											if ($field['exists'] == "true") {
												$response .= "<td class='row_style0' style=''>" . $text['option-true'] . "</td>\n";
												$response .= "<td>&nbsp;</td>\n";
											} else {
												$response .= "<td class='row_style1' style='background-color:#444444;color:#CCCCCC;'>" . $text['option-false'] . "</td>\n";
												$response .= "<td>&nbsp;</td>\n";
											}
											$response .= "</tr>\n";
										}
									}
									$response .= "	</table>\n";
									$response .= "</td>\n";
								}
							} else {
								$response .= "<td valign='top' class='row_style1'>$table_name</td>\n";
								$response .= "<td valign='top' class='row_style1' style='background-color:#444444;color:#CCCCCC;'><strong>" . $text['label-exists'] . "</strong><br />" . $text['option-false'] . "</td>\n";
								$response .= "<td valign='top' class='row_style1'>&nbsp;</td>\n";
							}
							$response .= "</tr>\n";
						}
					}
				}
				//end the list of tables
				$response .= "</table>\n";
				$response .= "<br />\n";
			}

			//loop line by line through all the lines of sql code
			$x = 0;
			if (empty($sql_update) && $format == "text") {
				$response .= "	" . $text['label-schema'] . ":			" . $text['label-no_change'] . "\n";
			} else {
				if ($format == "text") {
					$response .= "	" . $text['label-schema'] . "\n";
				}
				//$this->db->beginTransaction();
				$update_array = explode(";", $sql_update);
				foreach ($update_array as $sql) {
					if (strlen(trim($sql))) {
						try {
							$this->database->db->query(trim($sql));
							if ($format == "text") {
								$response .= "	$sql;\n";
							}
						} catch (PDOException $error) {
							$response .= "	error: " . $error->getMessage() . "	sql: $sql\n";
						}
					}
				}
				//$this->db->commit();
				$response .= "\n";
				unset($sql_update, $sql);
			}

			//refresh each postgresql subscription with its publication
			if ($db_type == "pgsql") {
				//get the list of postgresql subscriptions
				$sql = "select subname from pg_subscription; ";
				$pg_subscriptions = $this->database->select($sql, null, 'all');
				unset($sql, $parameters);

				//refresh each subscription publication
				foreach ($pg_subscriptions as $row) {
					$sql = "ALTER SUBSCRIPTION " . $row['subname'] . " REFRESH PUBLICATION;";
					$response .= $sql;
					$this->database->execute($sql);
				}
			}

			//handle response
			//if ($output == "echo") {
			//	echo $response;
			//}
			//else if ($output == "return") {
			return $response;
			//}
		} //end function
	}


//example use
//$obj = new schema;
//$obj->db_type = $db_type;
//$obj->schema();
//$result_array = $schema->obj['sql'];
//print_r($result_array);