Lightweight and simple Object Relational Mapping or ORM.

Only MySQL is supported and developed using PHP Data Object orPDO,but does not support CLI or Migration. you should have PDO extension activated on your php.ini ; Design by using Prepared Statements. Prepared Statements protect from SQL injection, and are very important for web application security.

In order to interact with the database, you should provide all required information. To create an instance you should provide database configuration such host,db_name,username and password, you can get instance of DB buy call getInstance method to get a singleton and take array config as parameters.

    use Wepesi\App\DB;
    $config=[
        "host"=>"localhost",
        "db_name"=>"wepesi_db",
        "username"=>"root",
        "password"=>""
    ];
    $db = DB::getInstance($config);

Now you have singleton of the database connection.

The Module help as some method build to help

• select => get
• insert => insert
• update => update
• delete => delete
• and transaction.

• get method is corresponding to SELECT, it helps to request the database, it as several chained method to help make request more interesting.

    use Wepesi\App\DB;
    $config = [
        "host" => "localhost",
        "db_name" => "wepesi_db",
        "username" => "root",
        "password" => ""];
    $db = DB::getInstance($config);
    $req = $db->get('message')->result();

• in the get method we have the first parameter witch is the table_name, then we call the result() method to execute your query and get result. the corresponding sql is:

    SELECT * FROM message;

in case you want to select specific field and apply a condition.

    $req = $db->get("message")->field(['userid','message'])->where(['userid',"=",1])->result();
    var_dump($req);

the corresponding SQL

    SELECT userid,message FROM message WHERE userid=1

• use field method to precise what are the field you want to get, all parameters should be passed on a simple array,
• use where method to add condition on the request and to use where method there is rule to follow. an array parameter to pass:
  • on the first position is the name of the field name as string,
  • on the second position is operation '<', '<=', '>', '>=', '<>', '!=', 'like', this only supported condition for more conditional better to write a [*QUERY](sql request).
  • The third position is the value of your condition,
  • and the forth position is for the operator and,orand not, by default it and, and it is required whene there is multiple conditiontions.

    $where = [
        ['id',"=",2],
        ['username',"like",'admin','or'],
        ['email',"like",'admin']
    ];
    $db->get("message")->field(['fname','lname'])->where($where)->result();

    SELECT fname,lname FROM message WHERE id=1 AND username like 'admin' or email like 'admin'; 

This is not all, you can LIMIT, OFFSET,groupBY,orderBy,ASC,DESC

    $where=[
        ['age',">",20]
    ];
    $db->get("users")->field(['email','address'])->where($where)->orderBy("id")->offset(0)->limit(30)->DESC()->result();

in case there is problem as error method can be called to check if there is any error.

$result = $db->get("users")->field(['email','address'])->orderBy("id")->offset(0)->limit(30)->DESC()->result();
if($db->error()) print_r($db->error());

Sometimes you want to count record instead if listing them, count method is part of get with return an object count. use count object to access the value return.

    $count_users = $db->count("users")->field(['email','address'])->where($where)->result();
    echo $count_users->count;
//

• insert is used to record data. the method take table name as parameter, use field method to pass data to be saved. in case your information are correct the db instance you can calllastId method to get the id of the inserted record.

    $data = [
        "userid" => 2,
        "message" => "hello from wepesi",
        "date_created" => Date('Y-m-d H:i:s')
    ];
    try {
            $db->insert("message")->field($data)->result();
            if ($this->db->error()) {
                throw new \Exception($this->db->error());
            }
            var_dump($this->db->lastId());
    } catch (\Exception $ex) {
        echo $ex->getMessage();
    }

the corresponding sql look like

    INSERT INTO message (`userid`,`message`,`datecreated`) VALUES (?,?,?)

• DELETE delete when you need to delete a record, this is the module to use. the same way you write where condition on get method is supported only for delete. it will return and array array("delete" => true) when the operation success.

    try {
        $req = $db->delete("message")->where(["id","=",16])->result();
        if ($this->db->error()) {
            throw new \Exception($this->db->error());
        }
        return $req;
    } catch (\Exception $ex) {
        echo $ex->getMessage();
    }

corresponding sql:

    DELETE `message` WHERE `id`='16'

• update when you need to update a record, this is the module to use. the same way you write where condition on delete method is supported only for delete. call rowCount method to get the number of record updated. You should call field method to specify witch field to be updated.

    try {
        $field = ["text" => "new messages from now"];
        $db->update("message")->field($field)->where(["id","=",16])->result();
        if ($this->db->error()) {
            throw new \Exception($this->db->error());
        }
        return $db->rowCount();
    } catch (\Exception $ex) {
        echo $ex->getMessage();
    }

corresponding sql:

    update `message`set text=? WHERE `id`='16'

• query : In case you have complex query,then you can use it.

    try{
        $req = $this->db->query("select * from message join users on users.id=message.userid");
        if($req->error()){
            throw new \Exception($req->error());
        }
        return $req->result();
    }catch(\Exception $ex){
        echo $ex->getMessage();
    }

the example bellow describe how it can be used. with the query method use the result() method to get the result.

For so many reasons you would like to implement a transaction in case one of your operation failed. Take caution only InnoDB support transaction in order to see the result you should be sure your ENGINE is innoDB, in case you are not sure about the database engine you can convert your tables only with convertMyISAMToInnoDB method. That method will help convert MyISAM engine to InnoDB. There are two ways to use transaction as been defined. you can manage by your own how, end when to apply transaction or use a builtin transaction method. It is recommended to use try catch in or to fulfil the operation.

• pdo transaction

The transaction has tree method to used in order to work properly, we have:

• beginTransaction : this method is used to start a transaction, and is shoudl be place at the beginning operation where the transaction will occur.
• commit : used this method when the operation succeeds.
• rollBack : is used to cancel all the operation.

  try{
  $user = [
    "fullname" => "Celestin Doe",
    "username" => "JohnDoe",
    "password" => md5("12345678"),
    "datecreated" => Date("Y-m-d H:i:s",time())
  ];  
  $message = [
      "message" => "Hello Celestin",
      'datecreated' => Date('Y-m-d H:i:s', time())
  ];
    $db->beginTransaction();
     $db->insert('users')->field($user)->result();
      if ($db->error()) {
          throw new \Exception($db->error());
      }
      
      $user_id = $db->lastId();
      $user['id'] = $user_id;
      $message['user_id'] = $user_id;
      $db->insert('message')->field($message)->result();
      if ($db->error()) {
          throw new \Exception($db->error());
      }
      $message['id'] = $db->lastId();
      
      $user['messages'] = $message;

      print_r($user);
      $db->commit();
  }
  catch(\Exception $ex){
    $db->rollBack();
  }

• Transaction as callback

method support closure method to be passed as parameter.
You don't need to manage every situation of the transaction, the method help you the focus implementation, and it will do the job for you.

    $user = [
      "fullname" => "Celestin Doe",
      "username" => "John Doe",
      "password" => md5("12345678"),
      "datecreated" => Date("Y-m-d H:i:s",time())
    ];
  
  $message = [
    "message" => "Hello Celestin",
    'datecreated' => Date('Y-m-d H:i:s', time())
  ];
  try {
    $db->transaction(function($db) use ($user,$message){
      $db->insert('users')->field($user)->result();
      if ($db->error()) {
        throw new \Exception($db->error());
      }
      $user_id = $db->lastId();
      $user['id'] = $user_id;
      $message['user_id'] = $user_id;
      $db->insert('message')->field($message)->result();
      if ($db->error()) {
        throw new \Exception($db->error());
      }
      $message['id'] = $db->lastId();
      $user['messages'] = $message;  
      print_r($user);
    });
  } catch (\Exception $ex) {
    var_dump($ex);
  }

• hope you enjoy. The ORM does not have join method or inclusion, on case to do that better to use *QUERY method.