DBSql Class: Database abstraction layer

This package implements a database abstraction layer.

It provides functions to perform several database access operations to different types of relational databases using the same interface. Currently it provide function to:

- Establish database connections
- Execute prepared or direct SQL queries
- Limit the range of result set rows that are returned by a query
- Retrieve the number of result set rows or affected database table rows
- Retrieve result set rows into arrays
- Execute INSERT, UPDATE and DELETE queries from a list of parameters
- Count or check if there is a database table records with a value in given field
- Retrieve the value returned by query results with a single column and row
- Retrieve all query result values into an bi-dimensional array
- Retrieve a range records from a table sorting by a given field

Currently this package provides driver classes to access to MySQL, SQLite and PostgreSQL databases.