DB Query Builder Class

dbase.php

<?php
/*
 * DB Query Builder Class
 * References:
 * Curtis Parham => https://www.youtube.com/playlist?list=PLFPkAJFH7I0keB1qpWk5qVVUYdNLTEUs3
 * MySQL => http://g2pc1.bu.edu/~qzpeng/manual/MySQL%20Commands.htm
 */
class Dbase {
	public static $_instance = null;
	private $_pdo, $_query, $_error = false, $_result, $_count = 0, $_lastInsertId = null, $_host = "localhost", $_db_name = "dbname", 
		    $_username = "username", $_password = "password";	

	public function __construct() {
		try {
			$this->_pdo = new PDO("mysql:host=".$this->_host.";dbname=".$this->_db_name,$this->_username,$this->_password);
		} catch (PDOException $e) {
			die($e->getMessage());
		}
	}

	public static function get_instance() {
		if (!isset(self::$_instance)) {
			self::$_instance = new Dbase();
		}
		return self::$_instance;
	}

	/*
	 * Query Execution
	*/
	public function query($sql, $params = []) {
		$this->_error = false;

		// prepare sql
		if ($this->_query = $this->_pdo->prepare($sql)) {
			$x = 1;
			
			// count params
			if (count($params)) {
				foreach ($params as $param) {
					$this->_query->bindValue($x,$param);
					$x++;
				}
			}

			// query execution
			if ($this->_query->execute()) {
				$this->_result = $this->_query->fetchALL(PDO::FETCH_OBJ);
				$this->_count = $this->_query->rowCount();
				$this->_lastInsertId = $this->_pdo->lastInsertId();
			} else {
				$this->_error = true;
			}			
		}
		return $this;
	}

	/*
	 * Read Values in Database
	 */
	protected function _read($table,$params = []) {
		$conditionString = '';
		$operator = '';
		$bind = [];
		$order = '';
		$limit = '';

		// Plot Conditions
		if (isset($params['conditions'])) {
			if (is_array($params['conditions'])) {
				$x = 0;
				foreach($params['conditions'] as $condition) {
					if (array_key_exists('operator',$params)) {
						$operator = $params['operator'];
					}								
					$conditionString .= ' '.$condition.' '.$operator[$x].' ? '.' AND';
					$x++;
				}
				$conditionString = trim($conditionString);
				$conditionString = rtrim($conditionString,', AND');
			} else {
				$conditionString = $params['conditions'];
			}
		}
		if ($conditionString != '') {
			$conditionString = ' WHERE '.$conditionString;
		}
		
		// Bind
		if (array_key_exists('bind', $params)) {
			$bind = $params['bind'];
		}

		// Order
		if (array_key_exists('order', $params)) {
			if ($params['order'] != '') {
				$order = ' ORDER BY '.$params['order'];
			}
		}

		// Limit
		if (array_key_exists('limit', $params)) {
			if ($params['limit'] != '') {					
				$limit = ' LIMIT '.$params['limit'];
			}
		}

		$sql = "SELECT * FROM {$table}{$conditionString}{$order}{$limit}";
		if ($this->query($sql,$bind)) {
			if (!count($this->_result)) return false;
			$this->count();
			return $this->result();
		}
		return false;
	}

	/*
	 * Simple Select
	 */
	public function select($table,$condition,$operator,$bind,$order='',$limit='') {
		$params = array();		
		$params['conditions'] = $condition;
		$params['operator'] = $operator;
		$params['bind'] = $bind;
		$params['order'] = $order;
		$params['limit'] = $limit;
		return $this->_read($table,$params);	
	}

	/*
	 * Like MySQL Statements
	 */
	public function like($table,$params = [],$before) {

	}

	/*
	 * Basic INSERT SQL Reference: INSERT INTO tablename (`fname`,`lname`) VALUES (?,?)
	*/
	public function insert($table, $fields = []) {
		$fieldString = '';
		$valueString = '';
		$values = [];
		foreach ($fields as $field => $value) {
			$fieldString .= '`'.$field.'`,';
			$valueString .= '?,';
			$values[] = $value; 
		}

		$fieldString = rtrim($fieldString,',');
		$valueString = rtrim($valueString,',');
		$sql = "INSERT INTO {$table} ({$fieldString}) VALUES ({$valueString})";
		
		if (!$this->query($sql,$values)->error()) {
			return true;
		} 
		return false;
	}

	/*
	 * Basic UPDATE SQL Reference: UPDATE tablename SET `fname` = ? WHERE `id` = $id
	*/
	public function update($table, $fields = [], $where = []) {
		$fieldString = '';
		$values = [];
		$whereString = '';
		foreach ($fields as $field => $value) {
			$fieldString .= '`'.$field.'`= ?,';
			$values[] = $value;
		}

		foreach ($where as $w => $val_w) {
			$whereString .= '`'.$w.'` = '.$val_w;
		}

		$fieldString = rtrim($fieldString,',');
		$sql = "UPDATE {$table} SET {$fieldString} WHERE {$whereString}";

		if (!$this->query($sql,$values)->error()) {
			return true;
		}
		return false;
	}	

	/*
	 * Basic DELETE SQL Reference: DELETE FROM tablename WHERE `id` = $id
	*/ 
	public function delete($table,$fields = [] ) {
		$fieldString = '';
		$values = [];
		foreach ($fields as $field => $value) {
			$fieldString .= '`'.$field.'`= ?';
			$values[] = $value;
		}
		$sql = "DELETE FROM {$table} WHERE {$fieldString}";

		if (!$this->query($sql,$values)->error()) {
			return true;
		}
		return false;
	}

	/*
	 * Generate Error
	 */
	public function error() {
		return $this->_error;
	}

	/*
	 * Return result
	 */
	public function result() {
		return $this->_result;
	}

	/*
	 * Return count
	 */
	public function count() {
		return $this->_count;
	}
}

Here is a PHP 7.4 version of your code. I hope people enjoy!

https://gist.github.com/jason-napolitano/6ef5ba92b62e39e952e6dd673d276eba