Query is a wrapper over a query that stores the name of the query and the query itself.

Client is a interface for a work with database.

DB is a interface for a work with database.

NamedExecer is a interface for a work with named queries using tags in structures.

Pinger is a interface for a checking a database connection.

QueryExecer is a interface for a work with common queries.

SQLExecer is a combine os QueryExecer and NamedExecer.

Transactor is a interface for work with transactions.

TxManager is a interface which manages specified handler inside transaction.

Handler - is a function which will be called inside transaction.