Connection's features

• the access to each type of DBMS is performed using a DBMS driver refered to as a provider which exists as a plugin

• many DBMS supported, see the providers' status page

• possibility to declare data sources (DSN), per-user or system wide
• each connection can be opened using a defined data source or using a connection string
• transactions and save points supported on a per-connection basis, and transaction status tracked
• introspection to query actual supported features
• introspection to retreive information about the actual database (data types, functions, tables, ...)

DML queries and data sets

Libgda's features regarding Data Manipulation queries (SELECT, INSERT, UPDATE and DELETE) are:

• powerfull SQL analyser which:
  • is able to delimiter individual SQL statements within a string containing several statements

  • for most queries can build a GdaQuery object where all the parts of the query are accessible for examination and modifications

  • supports a generic way of specifying place holders (variables)
• support for specifying how a SELECT query's result set will be accessed (random access or cursor based for large data sets), this feature however is not yet implemented in providers
• the data set returned after the execution of a SELECT query is fully introspectable
• the execution of a non SELECT query returns information about the number of impacted rows

Libgda's data sets returned by the execution of a SELECT query is an instance of a generic concept of a GdaDataModel which is a collection of data organized in a 2D array where the data of each column is of the same type. Libgda provides several implementations of that interface to support:

• import from CSV or XML files
• temporary modifications proxy
• subset proxy
• modifyable data set from a SELECT query

DDL queries

Libgda's features regarding Data Definition queries (all the queries which are not DML queries) are:

• support to create and drop databases
• support to create, alter and drop tables
• support to create and drop indexes

• each operation fully supports all the features of the actual DBMS being used

• extension to other kind of operation very easy becaused based on an XML specification

Note: the actual support depends on the implementation of each DBMS provider

Dictionary

Libgda implements a GdaDict dictionary object which exposes in a convenient way all the database structure:

• data types
• tables and view (and their fields)
• constraints

• more to come

Specifically the dictionary can:

• be updated (synchronized) with the database to reflect database structure's changes
• be saved and loaded from a file
• signal any change made to its contents