fix: use isset() when checking table property value (#52)

We can't access the `$this->table` property before initialization, so let's use `isset()` to check if the property has a value.

Reviewed-on: https://codeberg.org/vlw/php-mysql/pulls/52

.gitignore

@@ -0,0 +1,48 @@
+# Bootstrapping #
+#################
+/node_modules
+/public/hot
+/public/storage
+/storage/*.key
+/vendor
+.env
+.env.backup
+.phpunit.result.cache
+Homestead.json
+Homestead.yaml
+npm-debug.log
+yarn-error.log
+
+# OS generated files #
+######################
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+Icon?
+ehthumbs.db
+Thumbs.db
+.directory
+
+# Tool specific files #
+#######################
+# vim
+*~
+*.swp
+*.swo
+# sublime text & textmate
+*.sublime-*
+*.stTheme.cache
+*.tmlanguage.cache
+*.tmPreferences.cache
+# Eclipse
+.settings/*
+# JetBrains, aka PHPStorm, IntelliJ IDEA
+.idea/*
+# NetBeans
+nbproject/*
+# Visual Studio Code
+.vscode
+# Sass preprocessor
+.sass-cache/

README.md

@@ -1,53 +1,347 @@
-# php-libmysqldriver
+# php-mysql
 
-This library provides abstractions for parameter binding and result retrieval on MySQL(-like) databases in PHP. It is built on top of the PHP [`MySQL Improved`](https://www.php.net/manual/en/book.mysqli.php) extension.
+This is a simple abstraction library for MySQL DML operations.
 
-## Install with Composer
+For example:
+```php
+MySQL->from(string $table)
+  ->where(?array ...$conditions)
+  ->order(?array $order_by)
+  ->limit(?int $limit = null, ?int $offset = null)
+  ->select(string|array|null $columns = null): mysqli_result|bool;
+```
+which would be equivalent to the following in MySQL:
+```sql
+SELECT `columns` FROM `table` WHERE `filter` ORDER BY `order_by` LIMIT `limit`;
+```
+
+- All methods can be chained in any order (even multiple times) after a [`from()`](#from) as long as a [`select()`](#select), [`insert()`](#insert), [`update()`](#update), or [`delete()`](#delete) is the last method.
+- Chaining the same method more than once will override its previous value. Passing `null` to any method that accepts it will unset its value completely.
+
+## Install from composer
 
 ```
-composer require victorwesterlund/libmysqldriver
+composer require vlw/mysql
 ```
 
 ```php
-use libmysqldriver/MySQL;
+use vlw\MySQL\MySQL;
 ```
 
-## Usage
+> [!IMPORTANT]
+> This library requires the [`MySQL Improved`](https://www.php.net/manual/en/book.mysqli.php) extension and PHP 8.0 or newer.
 
-Connect to a MySQL database
+# Example / Documentation
+
+Available statements
+Statement|Method
+--|--
+`SELECT`|[`select()`](#select)
+`UPDATE`|[`update()`](#update)
+`INSERT`|[`insert()`](#insert)
+`DELETE`|[`delete()`](#delete)
+`WHERE`|[`where()`](#where)
+`ORDER BY`|[`order()`](#order-by)
+`LIMIT`|[`limit()`](#limit)
+
+----
+
+`Example table name: beverages`
+id|beverage_type|beverage_name|beverage_size
+--|--|--|--
+0|coffee|cappuccino|10
+1|coffee|black|15
+2|tea|green|10
+3|tea|black|15
 
 ```php
-use libysqldriver/MySQL;
+use vlw\MySQL\MySQL;
 
-$db = new MySQL(
+// Pass through: https://www.php.net/manual/en/mysqli.construct.php
-  "localhost:3306",
+$db = new MySQL($host, $user, $pass, $db);
-  "username",
-  "password",
-  "database"
-);
 ```
 
-Return matching rows from query (array of arrays)
+All executor methods [`select()`](#select), [`update()`](#update), and [`insert()`](#insert) will return a [`mysqli_result`](https://www.php.net/manual/en/class.mysqli-result.php) object or boolean.
+
+# FROM
 
 ```php
-$sql = "SELECT foo FROM table WHERE bar = ? AND biz = ?;
+MySQL->from(
+  string $table
+): self;
+```
 
-$response = $db->return_array($sql, [
+All queries start by chaining the `from(string $table)` method. This will define which database table the current query should be executed on.
-  "parameter_1",
+
-  "parameter_2
+*Example:*
+```php
+MySQL->from("beverages")->select("beverage_type");
+```
+
+# SELECT
+
+Chain `MySQL->select()` anywhere after a [`MySQL->from()`](#from) to retrieve columns from a database table.
+
+Pass an associative array of strings, CSV string, or null to this method to filter columns.
+
+```php
+MySQL->select(
+  string|array|null $columns
+): mysqli_result|bool;
+```
+
+In most cases you probably want to select with a constraint. Chain the [`where()`](#where) method before `select()` to filter the query
+
+### Example
+```php
+$`beverages` = MySQL->from("beverages")->select(["beverage_name", "beverage_size"]); // SELECT `beverage_name`, `beverage_size` FROM beverages
+```
+```
+[
+  [
+    "beverage_name" => "cappuccino",
+    "beverage_size" => 10
+  ],
+  [
+    "beverage_name" => "black",
+    "beverage_size" => 15
+  ],
+  // ...etc
+]
+```
+
+# INSERT
+
+Chain `MySQL->insert()` anywhere after a [`MySQL->from()`](#from) to append a new row to a database table.
+
+Passing a sequential array to `insert()` will assume that you wish to insert data for all defined columns in the table. Pass an associative array of `[column_name => value]` to INSERT data for specific columns (assuming the other columns have a [DEFAULT](https://dev.mysql.com/doc/refman/8.0/en/data-type-defaults.html) value defined).
+
+```php
+MySQL->insert(
+  // Array of values to INSERT
+  array $values
+): bool
+// Returns true if row was inserted
+```
+
+#### Example
+
+```php
+MySQL->from("beverages")->insert([
+  null,
+  "coffee",
+  "latte",
+  10
+]);
+// INSERT INTO `beverages` VALUES (null, "coffee", "latte", 10);
+```
+```
+true
+```
+
+# DELETE
+
+Chain `MySQL->delete()` anywhere after a [`MySQL->from()`](#from) to remove a row or rows from the a database table.
+
+```php
+MySQL->delete(
+  array ...$conditions
+): bool
+// Returns true if at least one row was deleted
+```
+
+This method takes at least one [`MySQL->where()`](#where)-syntaxed argument to determine which row or rows to delete. Refer to the [`MySQL->where()`](#where) section for more information.
+
+#### Example
+
+```php
+MySQL->from("beverages")->delete([
+  "beverage_name" => "coffee",
+]);
+// DELETE FROM `beverages` WHERE `beverage_name` = "coffee";
+```
+```
+true
+```
+
+# UPDATE
+
+Chain `MySQL->update()` anywhere after a [`MySQL->from()`](#from) to modify existing rows in a database table.
+
+```php
+MySQL->update(
+  // Key, value array of column names and values to update
+  array $fields,
+): mysqli_result|bool;
+// Returns true if at least 1 row was changed
+```
+
+### Example
+```php
+MySQL->from("beverages")->update(["beverage_size" => 10]); // UPDATE `beverages` SET `beverage_size` = 10
+```
+```php
+true
+```
+
+In most cases you probably want to UPDATE against a constaint. Chain a [`where()`](#where) method before [`MySQL->update()`](#update) to set constraints
+
+
+# WHERE
+
+Filter a [`MySQL->select()`](#select) or [`MySQL->update()`](#update) method by chaining the `MySQL->where()` method anywhere before it. The [`MySQL->delete()`](#delete) executor method also uses the same syntax for its arguments.
+
+Each key, value pair will be `AND` constrained against each other.
+
+```php
+MySQL->where(
+  ?array ...$conditions
+): self;
+```
+
+### Example
+```php
+$coffee = MySQL->from("beverages")->where(["beverage_type" => "coffee"])->select(["beverage_name", "beverage_size"]); // SELECT `beverage_name`, `beverage_size` FROM `beverages` WHERE (`beverage_type` = "coffee");
+```
+```php
+[
+  [
+    "beverage_name" => "cappuccino",
+    "beverage_size" => 10
+  ],
+  [
+    "beverage_name" => "black",
+    "beverage_size" => 15
+  ]
+]
+```
+
+## Capture groups
+
+### AND
+
+Add additional key value pairs to an array passed to `where()` and they will all be compared as AND with each other.
+
+```php
+MySQL->where([
+  "beverage_type" => "coffee",
+  "beverage_size" => 15
+]);
+```
+```sql
+WHERE (`beverage_type` = 'coffee' AND `beverage_size` = 15)
+```
+
+### OR
+
+Passing an additional array of key values as an argument will OR it with all other arrays passed.
+
+```php
+$filter1 = [
+  "beverage_type" => "coffee",
+  "beverage_size" => 15
 ];
 
-// Example $response with two matching rows: [["hello"],["world"]]
+$filter2 = [
-```
+  "beverage_type" => "tea",
-
+  "beverage_name" => "black"
-Return boolean if query matched at least one row, or if != `SELECT` query was sucessful
-
-```php
-$sql = "INSERT INTO table (foo, bar) VALUES (?, ?);
-
-$response = $db->return_bool($sql, [
-  "baz",
-  "qux"
 ];
 
-// Example $response if sucessful: true
+MySQL->where($filter1, $filter2, ...);
+```
+```sql
+WHERE (`beverage_type` = 'coffee' AND `beverage_size` = 15) OR (`beverage_type` = 'tea' AND `beverage_name` = 'black')
+```
+
+## Define custom operators
+
+By default, all values in an the assoc array passed to `where()` will be treated as an `EQUALS` (=) operator.
+
+```php
+MySQL->where(["column" => "euqals_this_value"]);
+```
+
+Setting the value of any key to another assoc array will allow for more "advanced" filtering by defining your own [`Operators`](https://github.com/VictorWesterlund/php-libmysqldriver/blob/master/src/Operators.php).
+
+The key of this subarray can be any MySQL operator string, or the **->value** of any case in the [`Operators`](https://github.com/VictorWesterlund/php-libmysqldriver/blob/master/src/Operators.php) enum.
+
+```php
+MySQL->where([
+  "beverage_name" => [
+    Operators::LIKE->value => "%wildcard_contains%"
+  ]
+]);
+```
+
+# ORDER BY
+
+Chain the `MySQL->order()` method before a [`MySQL->select()`](#select) statement to order by a specific column
+
+```php
+MySQL->order(
+  ?array $order_by
+): self;
+```
+
+```php
+$coffee = MySQL->from("beverages")->order(["beverage_name" => "ASC"])->select(["beverage_name", "beverage_size"]); // SELECT `beverage_name`, `beverage_size` FROM `beverages` ORDER BY `beverage_name` ASC
+```
+```php
+[
+  [
+    "beverage_name" => "tea",
+    "beverage_size" => 10
+  ],
+  [
+    "beverage_name" => "tea",
+    "beverage_size" => 15
+  ],
+  // ...etc for "`beverage_name` = coffee"
+]
+```
+
+# LIMIT
+
+Chain the `limit()` method before a [`MySQL->select()`](#select) statement to limit the amount of columns returned
+
+```php
+MySQL->limit(
+  ?int $limit,
+  ?int $offset = null
+): self;
+```
+
+## Passing a single integer argument
+This will simply `LIMIT` the results returned to the integer passed
+
+```php
+$coffee = MySQL->from("beverages")->limit(1)->select(["beverage_name", "beverage_size"]); // SELECT `beverage_name`, `beverage_size` FROM `beverages` WHERE `beverage_type` = "coffee" LIMIT 1
+```
+```php
+[
+  [
+    "beverage_name" => "cappuccino",
+    "beverage_size" => 10
+  ]
+]
+```
+
+## Passing two integer arguments
+This will `OFFSET` and `LIMIT` the results returned. The first argument will be the `LIMIT` and the second argument will be its `OFFSET`.
+
+```php
+$coffee = MySQL->from("beverages")->limit(3, 2)->select(["beverage_name", "beverage_size"]); // SELECT `beverage_name`, `beverage_size` FROM `beverages` LIMIT 3 OFFSET 2
+```
+```php
+[
+  [
+    "beverage_name" => "tea",
+    "beverage_size" => 10
+  ],
+  [
+    "beverage_name" => "tea",
+    "beverage_size" => 15
+  ],
+  // ...etc
+]
+```

composer.json

@@ -1,18 +1,18 @@
 {
-    "name": "victorwesterlund/libmysqldriver",
+    "name": "vlw/mysql",
-    "description": "Abstraction library for common mysqli features",
+    "description": "Abstraction library for common MySQL/MariaDB DML operations with php-mysqli",
     "type": "library",
-    "license": "GPL-3.0-only",
+    "license": "GPL-3.0-or-later",
     "authors": [
         {
             "name": "Victor Westerlund",
-            "email": "victor.vesterlund@gmail.com"
+            "email": "victor@vlw.se"
         }
     ],
     "minimum-stability": "dev",
     "autoload": {
         "psr-4": {
-            "libmysqldriver\\": "src/"
+            "vlw\\MySQL\\": "src/"
         }
     },
     "require": {}

composer.lock

@@ -0,0 +1,18 @@
+{
+    "_readme": [
+        "This file locks the dependencies of your project to a known state",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
+        "This file is @generated automatically"
+    ],
+    "content-hash": "aa59b0c90afdd92fd11d1cbc9352676c",
+    "packages": [],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "dev",
+    "stability-flags": [],
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": [],
+    "platform-dev": [],
+    "plugin-api-version": "2.0.0"
+}

src/MySQL.php

@@ -1,93 +1,286 @@
 <?php
 
-	namespace libmysqldriver;
+	namespace vlw\MySQL;
 
-	class MySQL extends \mysqli {
+	use Exception;
-		function __construct(string $host, string $user, string $pass, string $db) {
+	
-			parent::__construct($host, $user, $pass, $db);
+	use mysqli;
+	use mysqli_stmt;
+	use mysqli_result;
+
+	use vlw\MySQL\Order;
+	use vlw\MySQL\Operators;
+
+	require_once "Order.php";
+	require_once "Operators.php";
+
+	// Interface for MySQL_Driver with abstractions for data manipulation
+	class MySQL extends mysqli {
+		public ?array $columns = null;
+		
+		protected string $table;
+		protected ?string $limit = null;
+		protected ?string $order_by = null;
+		protected array $filter_columns = [];
+		protected array $filter_values = [];
+		protected ?string $filter_sql = null;
+
+		// Pass constructor arguments to driver
+		function __construct() {
+			parent::__construct(...func_get_args());
 		}
 
-		// Bind SQL statements
+		/*
-		private function bind_params(mysqli_stmt &$stmt, mixed $params) {
+			# Helper methods
-			// Make single-value, non-array, param an array with length of 1
+		*/
-			if (gettype($params) !== "array") {
-				$params = [$params];
-			}
 
-			// Concatenated string with types for each param
+		private function throw_if_no_table() {
-			$types = "";
+			if (!isset($this->table)) {
-
+				throw new Exception("No table name defined");
-			if (!empty($params)) {
-				// Convert PHP primitve to SQL primitive for params
-				foreach ($params as $param) {
-					switch (gettype($param)) {
-						case "integer":
-						case "double":
-						case "boolean":
-							$types .= "i";
-							break;
-
-						case "string":
-						case "array":
-						case "object":
-							$types .= "s";
-							break;
-
-						default:
-							$types .= "b";
-							break;
 			}
 		}
 
-				$stmt->bind_param($types, ...$params);
+		// Coerce input to single dimensional array
+		private static function to_list_array(mixed $input): array {
+			return array_values(is_array($input) ? $input : [$input]);
+		}
+
+		// Convert value to MySQL tinyint
+		private static function filter_boolean(mixed $value): int {
+			return (int) filter_var($value, FILTER_VALIDATE_BOOLEAN);
+		}
+
+		// Convert all boolean type values to tinyints in array
+		private static function filter_booleans(array $values): array {
+			return array_map(fn(mixed $v): mixed => gettype($v) === "boolean" ? self::filter_boolean($v) : $v, $values);
+		}
+
+		private static function array_wrap_accents(array $input): array {
+			return array_map(fn(mixed $v): string => "`{$v}`", $input);
+		}
+
+		/*
+			# Definers
+			These methods are used to build an SQL query by chaining methods together.
+			Defined parameters will then be executed by an Executer method.
+		*/
+
+		// Use the following table name
+		public function from(string $table): self {
+			// Reset all definers when a new query begins
+			$this->where();
+			$this->limit();
+			$this->order();
+
+			$this->table = $table;
+			return $this;
+		}
+
+		#[\Deprecated(
+			message: "use MySQL->from() instead",
+			since: "3.5.7",
+		)]
+		public function for(string $table): self {
+			return $this->from($table);
+		}
+
+		// Create a WHERE statement from filters
+		public function where(?array ...$conditions): self {
+			// Unset filters if null was passed
+			if ($conditions === null) {
+				$this->filter_sql = null;
+				$this->filter_columns = null;
+				$this->filter_values = null;
+
+				return $this;
+			}
+
+			$values = [];
+			$filters = [];
+
+			// Group each condition into an AND block
+			foreach ($conditions as $condition) {
+				$filter = [];
+
+				// Move along if the condition is empty
+				if (empty($condition)) {
+					continue;
+				}
+
+				// Create SQL string and append values to array for prepared statement
+				foreach ($condition as $col => $operation) {
+					$this->filter_columns[] = $col;
+
+					// Assume we want an equals comparison if value is not an array
+					if (!is_array($operation)) {
+						$operation = [Operators::EQUALS->value => $operation];
+					}
+
+					// Resolve all operator enum values in inner array
+					foreach ($operation as $operator => $value) {
+						// Null values have special syntax
+						if (is_null($value)) {
+							// Treat anything that isn't an equals operator as falsy
+							if ($operator !== Operators::EQUALS->value) {
+								$filter[] = "`{$col}` IS NOT NULL";
+								continue;
+							}
+
+							$filter[] = "`{$col}` IS NULL";	
+							continue;
+						}
+
+						// Create SQL for prepared statement
+						$filter[] = "`{$col}` {$operator} ?";
+						
+						// Append value to array with all other values
+						$values[] = $value;
 					}
 				}
 
-		// Execute an SQL query with a prepared statement
+				// AND together all conditions into a group
-		private function run_query(string $sql, mixed $params = null): mysqli_result|bool {
+				$filters[] = "(" . implode(" AND ", $filter) . ")";
-			$stmt = $this->prepare($sql);
-
-			// Bind parameters if provided
-			if ($params !== null) {
-				$this->bind_params($stmt, $params);
 			}
 
-			// Execute statement and get affected rows
+			// Do nothing if no filters were set
-			$query = $stmt->execute();
+			if (empty($filters)) {
-			$res = $stmt->get_result();
+				return $this;
-
-			// Return true if an INSERT, UPDATE or DELETE was sucessful (no rows returned)
-			if (!empty($query) && empty($res)) {
-				return true;
 			}
 
-			// Return mysqli_result object
+			// OR all filter groups
-			return $res;
+			$this->filter_sql = implode(" OR ", $filters);
+			// Set values property
+			$this->filter_values = $values;
+
+			return $this;
 		}
 
-		/* ---- */
+		// SQL LIMIT string
-
+		public function limit(?int $limit = null, ?int $offset = null): self {
-		// Get result as an associative array
+			// Unset row limit if null was passed
-		public function return_array(string $sql, mixed $params = null): array {
+			if ($limit === null) {
-			$query = $this->run_query($sql, $params);
+				$this->limit = null;
-
+				return $this;
-			$res = [];
-			while ($data = $query->fetch_assoc()) {
-				$res[] = $data;
 			}
 
-			return $res;
+			// Coerce offset to zero if no offset is defined
+			$offset = $offset ?? 0;
+
+			// Set limit and offset as SQL CSV
+			$this->limit = "{$offset},{$limit}";
+			return $this;
 		}
 
-		// Get only whether a query was sucessful or not
+		// Return SQL SORT BY string from assoc array of columns and direction
-		public function return_bool(string $sql, mixed $params = null): bool {
+		public function order(?array $order_by = null): self {
-			$query = $this->run_query($sql, $params);
+			// Unset row order by if null was passed
-
+			if ($order_by === null) {
-			// Return query if it's already a boolean
+				$this->order_by = null;
-			if (gettype($query) === "boolean") {
+				return $this;
-				return $query;
 			}
 
-			return $query->num_rows > 0 ? true : false;
+			// Assign Order Enum entries from array of arrays<Order|string>
+			$orders = array_map(fn(Order|string $order): Order => $order instanceof Order ? $order : Order::tryFrom($order), array_values($order_by));
+			// Create CSV string with Prepared Statement abbreviations from length of fields array.
+			$sql = array_map(fn(string $column, Order|string $order): string => "`{$column}` " . $order->value, array_keys($order_by), $orders);
+
+			$this->order_by = implode(",", $sql);
+			return $this;
+		}
+
+		/*
+			# Executors
+			These methods execute various statements that each return a mysqli_result
+		*/
+
+		// Create Prepared Statament for SELECT with optional WHERE filters
+		public function select(array|string|null $columns = null): mysqli_result|bool {
+			$this->throw_if_no_table();
+
+			// Create array of columns from CSV
+			$this->columns = is_array($columns) || is_null($columns) ? $columns : explode(",", $columns);
+
+			// Create CSV from columns or default to SQL NULL as a string
+			$columns_sql = $this->columns ? implode(",", self::array_wrap_accents($this->columns)) : "NULL";
+
+			// Create LIMIT statement if argument is defined
+			$limit_sql = !is_null($this->limit) ? " LIMIT {$this->limit}" : "";
+
+			// Create ORDER BY statement if argument is defined
+			$order_by_sql = !is_null($this->order_by) ? " ORDER BY {$this->order_by}" : "";
+
+			// Get array of SQL WHERE string and filter values
+			$filter_sql = !is_null($this->filter_sql) ? " WHERE {$this->filter_sql}" : "";
+
+			// Interpolate components into an SQL SELECT statmenet and execute
+			$sql = "SELECT {$columns_sql} FROM `{$this->table}`{$filter_sql}{$order_by_sql}{$limit_sql}";
+			// Return mysqli_response of matched rows
+			return $this->execute_query($sql, self::to_list_array($this->filter_values));
+		}
+
+		// Create Prepared Statement for UPDATE using PRIMARY KEY as anchor
+		public function update(array $entity): mysqli_result|bool {
+			$this->throw_if_no_table();
+
+			// Create CSV string with Prepared Statement abbreviations from length of fields array.
+			$changes = array_map(fn($column) => "`{$column}` = ?", array_keys($entity));
+			$changes = implode(",", $changes);
+
+			// Get array of SQL WHERE string and filter values
+			$filter_sql = !is_null($this->filter_sql) ? " WHERE {$this->filter_sql}" : "";
+
+			// Get values from entity and convert booleans to tinyint
+			$values = self::filter_booleans(array_values($entity));
+			
+			// Append values to filter property if where() was chained
+			if ($this->filter_values) {
+				array_push($values, ...$this->filter_values);
+			}
+
+			// Interpolate components into an SQL UPDATE statement and execute
+			$sql = "UPDATE `{$this->table}` SET {$changes} {$filter_sql}";
+			return $this->execute_query($sql, self::to_list_array($values));
+		}
+
+		// Create Prepared Statemt for INSERT
+		public function insert(array $values): mysqli_result|bool {
+			$this->throw_if_no_table();
+
+			/*
+				Use array keys from $values as columns to insert if array is associative.
+				Treat statement as an all-columns INSERT if the $values array is sequential.
+			*/
+			$columns = !array_is_list($values) ? "(" . implode(",", array_keys($values)) . ")" : "";
+
+			// Convert booleans to tinyint
+			$values = self::filter_booleans($values);
+
+			// Create CSV string with Prepared Statement abbreviatons from length of fields array.
+			$values_stmt = implode(",", array_fill(0, count($values), "?"));
+
+			// Interpolate components into an SQL INSERT statement and execute
+			$sql = "INSERT INTO `{$this->table}` {$columns} VALUES ({$values_stmt})";
+			return $this->execute_query($sql, self::to_list_array($values));
+		}
+
+		// Create Prepared Statemente for DELETE with WHERE condition(s)
+		public function delete(array ...$conditions): mysqli_result|bool {
+			$this->throw_if_no_table();
+
+			// Set DELETE WHERE conditions from arguments
+			if ($conditions) {
+				$this->where(...$conditions);
+			}
+
+			// Get array of SQL WHERE string and filter values
+			$filter_sql = !is_null($this->filter_sql) ? " WHERE {$this->filter_sql}" : "";
+
+			$sql = "DELETE FROM `{$this->table}`{$filter_sql}";
+			return $this->execute_query($sql, self::to_list_array($this->filter_values));
+		}
+
+		// Execute SQL query with optional prepared statement and return mysqli_result
+		public function exec(string $sql, mixed $params = null): mysqli_result {
+			return $this->execute_query($sql, self::to_list_array($params));
 		}
 	}

src/Operators.php

@@ -0,0 +1,46 @@
+<?php
+
+	namespace vlw\MySQL;
+
+	enum Operators: string {
+		// Logical
+		case ALL     = "ALL";
+		case AND     = "AND";
+		case ANY     = "ANY";
+		case BETWEEN = "BETWEEN";
+		case EXISTS  = "EXISTS";
+		case IN      = "IN";
+		case LIKE    = "LIKE";
+		case NOT     = "NOT";
+		case OR      = "OR";
+		case SOME    = "SOME";
+
+		// Comparison
+		case EQUALS = "=";
+		case GT     = ">";
+		case LT     = "<";
+		case GTE    = ">=";
+		case LTE    = "<=";
+		case NOTE   = "<>";
+
+		// Arithmetic
+		case ADD      = "+";
+		case SUBTRACT = "-";
+		case MULTIPLY = "*";
+		case DIVIDE   = "/";
+		case MODULO   = "%"; 
+
+		// Bitwise
+		case BS_AND = "&";
+		case BS_OR  = "|";
+		case BS_XOR = "^";
+
+		// Compound
+		case ADDE    = "+=";
+		case SUBE    = "-=";
+		case DIVE    = "/=";
+		case MODE    = "%=";
+		case BS_ANDE = "&=";
+		case BS_ORE  = "|*=";
+		case BS_XORE = "^-=";
+	}

src/Order.php

@@ -0,0 +1,8 @@
+<?php
+
+	namespace vlw\MySQL;
+
+	enum Order: string {
+		case ASC  = "ASC";
+		case DESC = "DESC";
+	}