Download the PHP package webfiori/database without Composer

Webfiori Database Abstraction Layer

Database abstraction layer of WebFiori framework.

Content

• Supported PHP Versions
• Supported Databases
• Features
• Installation
• Usage
  • Connecting to Database
  • Running Basic SQL Queries
  • Insert Query
  • Select Query
  • Update Query
  • Delete Query
  • Building Database Structure
  • Creating Table Blueprint
  • Seeding Structure to Database
  • Creating Entity Classes and Using Them
  • Creating an Entity Class
  • Using Entity Class

Supported PHP Versions

Build Status

Supported Databases

• MySQL
• MSSQL

Features

• Building your database structure within PHP.
• Fast and easy to use query builder.
• Database abstraction which makes it easy to migrate your system to different DBMS.

Installation

To install the library using composer, add following dependency to composer.json: "webfiori/database":"*"

Usage

Connecting to Database

Connecting to a database is simple. First step is to define database connection information using the class ConnectionInfo. Later, the instance can be used to establish a connection to the database using the class Database.

Running Basic SQL Queries

Most common SQL queries that will be executed in any relational DBMS are insert, select, update, and delete. Following examples shows how the 4 types can be constructed.

For every query, the table that the query will be executed on must be specified. To specify the table, the method Database::table(string $tblName). The method will return an instance of the class AbstractQuery. The class AbstractQuery has many methods which are used to further build the query. Commonly used methods include the following:

• AbstractQuery::insert(array $cols): Construct an insert query.
• AbstractQuery::select(array $cols): Construct a select query.
• AbstractQuery::update(array $cols): Construct an update query.
• AbstractQuery::delete(): Construct a delete query.
• AbstractQuery::where($col, $val): Adds a condition to the query.

After building the query, the method AbstractQuery::execute() can be called to execute the query. If the query is a select query, the method will return an instance of the class ResultSet. The instance can be used to traverse the records that was returned by the DBMS.

Insert Query

Insert query is used to add records to the database. To execute an insert query, the method AbstractQuery::insert(array $cols). The method accepts one parameter. The parameter is an associative array. The indices of the array are columns names and the values of the indices are the values that will be inserted.

Select Query

A select query is used to fetch database records and use them in application logic. To execute a select query, the method AbstractQuery::select(array $cols). The method accepts one optional parameter. The parameter is an array that holds the names of the columns that will be selected. In this case, the method AbstractQuery::execute() will return an object of type ResultSet. The result set will contain raw fetched records as big array that holds the actual records. Each record is stored as an associative array.

It is possible to add a condition to the select query using the method AbstractQuery::where().

Update Query

Update query is used to update a single record or multiple records. To execute an update query, the method AbstractQuery::update(array $cols). The method accepts one parameter. The parameter is an associative array. The indices of the array are columns names and the values of the indices are the updated values. Usually, for any update query, a where condition will be included. To include a where condition, the method AbstractQuery::where() can be used.

Delete Query

This query is used to delete specific record from the database. To execute delete query, the method AbstractQuery::delete(). A where condition should be included to delete specific record. To include a where condition, the method AbstractQuery::where() can be used.

Building Database Structure

One of the features of the library is the ability to define database structure in the source code and later, seed the created structure to create database tables. The blueprint of tables are represented by the class Table. The main aim of the blueprint is to make sure that data types in database are represented correctly in the source code.

Note: Sample source code on how to build the structure can be found here.

Creating Table Blueprint

Each blueprint must have following attributes defined:

• Name of the blueprint (database table name).
• Columns and thier properties such as data type.
• Any relations with other tables.

The method Database::createBlueprint() is used to create a table based on connected DBMS. The method will return an instance of the class Table which can be used to further customize the blueprint.

Note: It is possible to represent the blueprint using classes. A sample blueprint as class can be found here.

Seeding Structure to Database

After creating all blueprints, a query must be structured and executed to create database tables. Building the query can be performed using the method Database::createTables(). After calling this method, the method Database::execute() must be called to create all database tables.

Creating Entity Classes and Using Them

Entity classes are classes which are based on blueprints (or tables). They can be used to map records of tables to objects. Every blueprint will have an instance of the class EntityMapper which can be used to create an entity class.

Entity classes that are generated using the class EntityMapper are special. They will have one static method with name map() which can automatically map a record to an instance of the entity.

Creating an Entity Class

First step in creating an entity is to have the blueprint at which the entity will be based on. From the bluprint, an instance of the class EntityMapper is generated. After having the instance, the probperties of the entity is set such as its name, namespace and where it will be created. Finally, the method EntityMapper::create() can be invoked to write the source code of the class.

Using Entity Class

Entity class can me used to map a record to an object. Each entity will have a special method called map(). The method accepts a single paramater which is an associative array that represents fetched record.

The result set instance has one of array methods which is called map($callback) This method acts exactly as the function array_map($callback, $array). The return value of the method is another result set with mapped records.

Transaction

Suppose that in the database there are 3 tables, user_info, user_login and user_contact. In order to have a full user profile, user information must exist on the 3 tables at same time. Suppose that record creation in the first and second table was a success. But due some error, the record was not created in the last table. This would cause data interty error. To resolve this, the insertion process must be rolled back. In such cases, database transactions can be of great help.

A database transaction is a unit of work which consist of multiple operations that must be performed togather. If one operation fail, then all operations must be rolled back. A transaction can be initiated using the method Database::transaction(). The method has two arguments, first one is the logic of the transaction as closure and second one is an optional array of arguments to be passed to the cloasure. The first parameter of the closure will be always an instance of Database.

If the closure returns false or the closure throws a DatabaseException, the transaction is rolled back.