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Xojo Database API in the V4RB plugin

Xojo has its own special Database API documented in the Xojo documentation: https://documentation.xojo.com/api/databases/index.html

In previous versions of Xojo or REALbasic, this was referred to as the RBDB API and to use it required that you license a version of Xojo that supports this specific API. In this documentation, we refer to this as the Xojo Database API.

Overview of Xojo Database API

The Xojo Database API is an attempt to offer a unified API to access different databases. Because of this, the API tends to be minimalistic:

  • Database - main class
  • RowSet - Result of SelectSQL().
  • DatabaseRow - optional, helper class for Database.AddRow() method.
  • PreparedSQLStatement - helper class, produced by Database.Prepare() method. Allows using SQL queries with bound parameters.

Abstract class 'Database' and set of database-specific sub-classes:

  • MSSQLServerDatabase
  • MySQLCommunityServer
  • ODBCDatabase
  • OracleDatabase
  • PostgreSQLDatabase
  • SQLiteDatabase

There are important differences in those classes between SQLite and others, because SQLite is a local DB engine, while others are remote DB SQL Servers.

  • SQLiteDatabase class has property db.DatabaseFile, which means the path on HDD to a database file. Remote DB classes use db.DatabaseName property to specify just database name.
  • SQLiteDatabase class has method CreateDatabase() to create database on disk and Connect() to open. Remote DB classes have DB.connect() method only.

V4RB Plugin and Xojo Database API

Starting with v6.0, V4RB plugin adds support for SQLite and provides 'Xojo Database API' for 2 databases:

  • Valentina DB (Local and Client to Valentina DB Server) via class VRBDatabase.
  • SQLite DB (Local and Client to Valentina SQLite Server) via class VSqliteDataBase.

Both these classes inherit directly from the Database class of Xojo, so all its properties and methods can be used as described in the documentation of Xojo.

Xojo Database API for SQLite

The V4RB plugin provides the following for SQLite databases:

  • access to local SQLite databases
  • access to the SQLite implementation in the Valentina SQLite Server portion of Valentina Server

For the purposes of support and easy porting of solutions then, we provide:

  1. similar API for SqliteDatabase and VSqliteDatabase classes
  2. similar API for local and remote work

By maintaining this similarity, it allows you to

  1. easily migrate existing code of your Xojo app from built-in SQLite classes to the Valentina SQLite implementation
  2. have the same code working with both local and client-server SQLite databases

Xojo Database API for Valentina DB

VRBDatabase Class

The Valentina implementation of this class is minimal because

  1. Valentina developers prefer to use Valentina Native API, which provides more power and flexibility over the limitations of the VRBDatabase Class framework
  2. You can switch from the VRBDatabase class to VDatabase class if it is necessary to take advantage of more features

Properties:

* ConnectionTimeout as Integer
* DatabaseFile as FolderItem
* Port as Integer
* EmbeddedSerial as String
* StructureEncryptionKey as String  // new since v.10.4.16
* DataEncryptionKey as String       // new since v.10.4.16

Methods:

* Connect() as boolean
* CreateDataBaseFile() as boolean
* OpenDataBaseFile() as boolean
* OpenBLOB( inTableName as string, inFieldName as string, inRowID as Int64, inReadWrite as boolean ) As VSqliteBLOB

You can easily switch from Xojo Database classes for Valentina to native Valentina API classes with the help of VDatabase.Constructor( VRBDatabase inDB ). See Valentina Reference.pdf for details.

Example:

Dim dbFile as FolderItem
Dim db as VRBDataBase

db = new VRBDataBase

if gClient then
  db.Host = "localhost"
  db.UserName = "sa"
  db.Password = "sa"
  db.Port = 15432
  db.databaseName = filename
else
  dbFile = GetFolderItem(filename)
  db.databaseFile = dbFile
end if

// Optionally set encryption keys: 
db.StructureEncryptionKey = "456"
db.DataEncryptionKey = "123"

if db.Connect then
...