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

README.md

@@ -4,19 +4,19 @@ This is a simple abstraction library for MySQL DML operations.
 
 For example:
 ```php
-MySQL->for(string $table)
+MySQL->from(string $table)
   ->where(?array ...$conditions)
   ->order(?array $order_by)
-  ->limit(int|array|null $limit)
+  ->limit(?int $limit = null, ?int $offset = null)
-  ->select(array $columns): array|bool;
+  ->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;
+SELECT `columns` FROM `table` WHERE `filter` ORDER BY `order_by` LIMIT `limit`;
 ```
 
-> [!IMPORTANT]
+- 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.
-> This library requires the [`MySQL Improved`](https://www.php.net/manual/en/book.mysqli.php) extension and requires PHP 8.0 or newer.
+- 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
 
@@ -28,6 +28,9 @@ composer require vlw/mysql
 use vlw\MySQL\MySQL;
 ```
 
+> [!IMPORTANT]
+> This library requires the [`MySQL Improved`](https://www.php.net/manual/en/book.mysqli.php) extension and PHP 8.0 or newer.
+
 # Example / Documentation
 
 Available statements
@@ -60,30 +63,30 @@ $db = new MySQL($host, $user, $pass, $db);
 
 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.
 
-# FOR
+# FROM
 
 ```php
-MySQL->for(
+MySQL->from(
   string $table
 ): self;
 ```
 
-All queries start by chaining the `for(string $table)` method. This will define which database table the current query should be executed on.
+All queries start by chaining the `from(string $table)` method. This will define which database table the current query should be executed on.
 
 *Example:*
 ```php
-MySQL->for("beverages")->select("beverage_type");
+MySQL->from("beverages")->select("beverage_type");
 ```
 
 # SELECT
 
-Chain `MySQL->select()` anywhere after a [`MySQL->for()`](#for) to retrieve columns from a database table.
+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(
-  array|string|null $columns
+  string|array|null $columns
 ): mysqli_result|bool;
 ```
 
@@ -91,7 +94,7 @@ In most cases you probably want to select with a constraint. Chain the [`where()
 
 ### Example
 ```php
-$beverages = MySQL->for("beverages")->select(["beverage_name", "beverage_size"]); // SELECT beverage_name, beverage_size FROM beverages
+$`beverages` = MySQL->from("beverages")->select(["beverage_name", "beverage_size"]); // SELECT `beverage_name`, `beverage_size` FROM beverages
 ```
 ```
 [
@@ -109,7 +112,7 @@ $beverages = MySQL->for("beverages")->select(["beverage_name", "beverage_size"])
 
 # INSERT
 
-Chain `MySQL->insert()` anywhere after a [`MySQL->for()`](#for) to append a new row to a database table.
+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).
 
@@ -117,20 +120,20 @@ Passing a sequential array to `insert()` will assume that you wish to insert dat
 MySQL->insert(
   // Array of values to INSERT
   array $values
-): mysqli_result|bool
+): bool
 // Returns true if row was inserted
 ```
 
 #### Example
 
 ```php
-MySQL->for("beverages")->insert([
+MySQL->from("beverages")->insert([
   null,
   "coffee",
   "latte",
   10
 ]);
-// INSERT INTO beverages VALUES (null, "coffee", "latte", 10);
+// INSERT INTO `beverages` VALUES (null, "coffee", "latte", 10);
 ```
 ```
 true
@@ -138,12 +141,12 @@ true
 
 # DELETE
 
-Chain `MySQL->delete()` anywhere after a [`MySQL->for()`](#for) to remove a row or rows from the a database table.
+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
-): mysqli_result|bool
+): bool
 // Returns true if at least one row was deleted
 ```
 
@@ -152,13 +155,10 @@ This method takes at least one [`MySQL->where()`](#where)-syntaxed argument to d
 #### Example
 
 ```php
-MySQL->for("beverages")->insert([
+MySQL->from("beverages")->delete([
-  null,
+  "beverage_name" => "coffee",
-  "coffee",
-  "latte",
-  10
 ]);
-// INSERT INTO beverages VALUES (null, "coffee", "latte", 10);
+// DELETE FROM `beverages` WHERE `beverage_name` = "coffee";
 ```
 ```
 true
@@ -166,7 +166,7 @@ true
 
 # UPDATE
 
-Chain `MySQL->update()` anywhere after a [`MySQL->for()`](#for) to modify existing rows in a database table.
+Chain `MySQL->update()` anywhere after a [`MySQL->from()`](#from) to modify existing rows in a database table.
 
 ```php
 MySQL->update(
@@ -178,7 +178,7 @@ MySQL->update(
 
 ### Example
 ```php
-MySQL->for("beverages")->update(["beverage_size" => 10]); // UPDATE beverages SET beverage_size = 10
+MySQL->from("beverages")->update(["beverage_size" => 10]); // UPDATE `beverages` SET `beverage_size` = 10
 ```
 ```php
 true
@@ -201,7 +201,7 @@ MySQL->where(
 
 ### Example
 ```php
-$coffee = MySQL->for("beverages")->where(["beverage_type" => "coffee"])->select(["beverage_name", "beverage_size"]); // SELECT beverage_name, beverage_size FROM beverages WHERE (beverage_type = "coffee");
+$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
 [
@@ -229,7 +229,7 @@ MySQL->where([
 ]);
 ```
 ```sql
-WHERE (beverage_type = 'coffee' AND beverage_size = 15)
+WHERE (`beverage_type` = 'coffee' AND `beverage_size` = 15)
 ```
 
 ### OR
@@ -250,7 +250,7 @@ $filter2 = [
 MySQL->where($filter1, $filter2, ...);
 ```
 ```sql
-WHERE (beverage_type = 'coffee' AND beverage_size = 15) OR (beverage_type = 'tea' AND beverage_name = 'black')
+WHERE (`beverage_type` = 'coffee' AND `beverage_size` = 15) OR (`beverage_type` = 'tea' AND `beverage_name` = 'black')
 ```
 
 ## Define custom operators
@@ -284,7 +284,7 @@ MySQL->order(
 ```
 
 ```php
-$coffee = MySQL->for("beverages")->order(["beverage_name" => "ASC"])->select(["beverage_name", "beverage_size"]); // SELECT beverage_name, beverage_size FROM beverages ORDER BY beverage_name ASC
+$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
 [
@@ -296,7 +296,7 @@ $coffee = MySQL->for("beverages")->order(["beverage_name" => "ASC"])->select(["b
     "beverage_name" => "tea",
     "beverage_size" => 15
   ],
-  // ...etc for "beverage_name = coffee"
+  // ...etc for "`beverage_name` = coffee"
 ]
 ```
 
@@ -315,7 +315,7 @@ MySQL->limit(
 This will simply `LIMIT` the results returned to the integer passed
 
 ```php
-$coffee = MySQL->for("beverages")->limit(1)->select(["beverage_name", "beverage_size"]); // SELECT beverage_name, beverage_size FROM beverages WHERE beverage_type = "coffee" LIMIT 1
+$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
 [
@@ -330,7 +330,7 @@ $coffee = MySQL->for("beverages")->limit(1)->select(["beverage_name", "beverage_
 This will `OFFSET` and `LIMIT` the results returned. The first argument will be the `LIMIT` and the second argument will be its `OFFSET`.
 
 ```php
-$coffee = MySQL->for("beverages")->limit(3, 2)->select(["beverage_name", "beverage_size"]); // SELECT beverage_name, beverage_size FROM beverages LIMIT 3 OFFSET 2
+$coffee = MySQL->from("beverages")->limit(3, 2)->select(["beverage_name", "beverage_size"]); // SELECT `beverage_name`, `beverage_size` FROM `beverages` LIMIT 3 OFFSET 2
 ```
 ```php
 [

src/MySQL.php

@@ -8,22 +8,23 @@
 	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 {
-		private string $table;
-
-		private ?string $limit = null;
-		private ?string $order_by = null;
-		private array $filter_values = [];
-		private ?string $filter_sql = null;
-
-		// Array of last SELECT-ed columns
 		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());
@@ -34,7 +35,7 @@
 		*/
 
 		private function throw_if_no_table() {
-			if (!$this->table) {
+			if (!isset($this->table)) {
 				throw new Exception("No table name defined");
 			}
 		}
@@ -51,7 +52,11 @@
 
 		// Convert all boolean type values to tinyints in array
 		private static function filter_booleans(array $values): array {
-			return array_map(fn($v): mixed => gettype($v) === "boolean" ? self::filter_boolean($v) : $v, $values);
+			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);
 		}
 
 		/*
@@ -61,7 +66,7 @@
 		*/
 
 		// Use the following table name
-		public function for(string $table): self {
+		public function from(string $table): self {
 			// Reset all definers when a new query begins
 			$this->where();
 			$this->limit();
@@ -71,11 +76,20 @@
 			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;
@@ -95,6 +109,8 @@
 
 				// 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];
@@ -147,17 +163,8 @@
 				return $this;
 			}
 
-			// Set LIMIT without range directly as integer
+			// Coerce offset to zero if no offset is defined
-			if (is_int($limit)) {
+			$offset = $offset ?? 0;
-				$this->limit = $limit;
-				return $this;
-			}
-
-			// No offset defined, set limit property directly as string
-			if (is_null($offset)) {
-				$this->limit = (string) $limit;
-				return $this;
-			}
 
 			// Set limit and offset as SQL CSV
 			$this->limit = "{$offset},{$limit}";
@@ -172,12 +179,12 @@
 				return $this;
 			}
 
-			// Create CSV from columns
+			// Assign Order Enum entries from array of arrays<Order|string>
-			$sql = implode(",", array_keys($order_by));
+			$orders = array_map(fn(Order|string $order): Order => $order instanceof Order ? $order : Order::tryFrom($order), array_values($order_by));
-			// Create pipe DSV from values 
+			// Create CSV string with Prepared Statement abbreviations from length of fields array.
-			$sql .= " " . implode("|", array_values($order_by));
+			$sql = array_map(fn(string $column, Order|string $order): string => "`{$column}` " . $order->value, array_keys($order_by), $orders);
 
-			$this->order_by = $sql;
+			$this->order_by = implode(",", $sql);
 			return $this;
 		}
 
@@ -194,7 +201,7 @@
 			$this->columns = is_array($columns) || is_null($columns) ? $columns : explode(",", $columns);
 
 			// Create CSV from columns or default to SQL NULL as a string
-			$columns_sql = $this->columns ? implode(",", $this->columns) : "NULL";
+			$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}" : "";
@@ -216,7 +223,7 @@
 			$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));
+			$changes = array_map(fn($column) => "`{$column}` = ?", array_keys($entity));
 			$changes = implode(",", $changes);
 
 			// Get array of SQL WHERE string and filter values
@@ -261,9 +268,14 @@
 			$this->throw_if_no_table();
 
 			// Set DELETE WHERE conditions from arguments
-			$this->where(...$conditions);
+			if ($conditions) {
+				$this->where(...$conditions);
+			}
 
-			$sql = "DELETE FROM `{$this->table}` WHERE {$this->filter_sql}";
+			// 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));
 		}
 

src/Order.php

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