DB-Adapter is a library to provide an abstract interface to database functionality (much like ODBC). The interface is still under development, and should be considered alpha – incompatible changes will be made without notice.
The interface covers basic db operations like connecting and disconnecting, committing or rolling back transactions, executing SQL statements, and data-management operations that are likely to be non-standard across databases. It does not attempt to normalize or generate SQL statements – clients will have to make their own arrangements for portable queries.
ODBC also aims to provide an abstract interface to multiple databases, and it does quite well at providing baseline functionality. However, ODBC is foreign code which requires wrappers, and the nature of its ABI make it difficult to add support for db features that don’t fit within the ODBC model. This library aims to make it at least possible to use additional features, as long as clients are willing to manage the portability issues.
cl-dbi is explicitly a database-compatibility library, and has
gained some popularity. There are issues with it that this library
tries to avoid:
- interns keywords at runtime (from column names, so you can get
wacky keywords like
:|sum(avg(item_price))|) - uses plists for result sets, so it conses twice as much as it needs to per row
- supports cursor-style queries, but the API doesn’t support foreign drivers like ODBC (it lacks cleanup support)
- the driver API is under-specified, which makes it difficult to write new drivers (methods are sometimes specced to return “something”, with no indication where that value will be used)
- the API is more focused than this library, and doesn’t include some useful data-management facilities.
clsql uses a system of adapters to address database portability
issues. Unlike clsql, this library does not intend to include
sql-generating DSLs or an ORM.