Table Data Gateway (Software Design)

A Table Data Gateway provides an interface to the table of a database.

The interface maps semantics of native SQL-commands to its interface-methods, such as INSERT, UPDATE, DELETE and SELECT.

Additional methods might be added to the Gateway, e.g. for querying data based on more complex filter criteria.

For reconstituting more complex Domain Models, such as Aggregates, Data Mappers can be used.

Example

The following class provides an interface for a Table Data Gateway for an Employee-table:

info

(SQL-)code intentionally simplified for demonstration purposes.

EmployeeTableDataGateway.php

class EmployeeTableDataGateway {


    public function insert(string $empId, string $name, string $address): string
    {
        $sql = "INSERT INTO employee (emp_id, name, address) VALUES ('$empId', '$name', '$address')";

        return $this->dbConn->execute($sql);
    }


    public function update(string $empId, string $name, string $address): bool
    {
        $sql = "UPDATE employee SET emp_id='$empId', name='$name', address='$address'";

        return $this->dbConn->execute($sql);
    }


    public function find(string $empId): array
    {
        $sql = "SELECT FROM employee WHERE emp_id='$empId'";

        return $this->executeSelect($sql);
    }


    public function findByCompany(string $companyId): array
    {
        $sql = "SELECT FROM employee WHERE company_id='$companyId'";

        return $this->executeSelect($sql);
    }
}

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Table Data Gateway (Software Design)

Example​

Example