# Part VII. Databases providers for developers

For each database engine, Libgda requires an object which maps Libgda's API to the native API offered by that database engine. That object, a database provider needs to inherit GdaServerProvider and implement its virtual methods.

Database provider objects are generally instantiated once by the Libgda framework and can be used several times to open and work on connections to several databases of the same type.

Since Libgda itself is developed in the C language, and that most providers are also implemented in that language, the Libgda library itself contains a set of helper classes and functions to guide you in the addition of a new provider to the GDA framework. Two reference implementations are provided in the `providers/skel-implementation` directory of Libgda's sources:

- in `providers/skel-implementation/capi`: a skeleton implementation from scratch for a database accessed through a C API, where all the methods to implement are partially coded

- in `providers/skel-implementation/models`: a skeleton implementation to write a provider for sources which are not databases (which do not implement any SQL) such as the Berkeley DB provider (a BDB database is a key/value collection) or the MDB (MS Access files) provider. This kind of provider "export" tables which are in fact data models.

The helper objects and functions to write database providers are documented in the Providers' support API section.