The libpq interface is still available for C programs. A sample shell, pgtclsh, provides new Tcl commands to interface tcl programs with the Postgres95 backend. The large object interface has been overhauled. We kept Inversion large objects as the only mechanism for storing large objects. The instance-level rule system has been removed.
Rules are still available as rewrite rules.
A short tutorial introducing regular SQL features as well as those of ours is distributed with the source code. A new name, PostgreSQL, was chosen to reflect the relationship between original Postgres and the more recent versions with SQL capability. The emphasis on development for the v1.0.x releases of Postgres95 was on stabilizing the backend code. Additional SQL92-compliant language features have been added, including primary keys, quoted identifiers, literal string type coersion, type casting, and binary and hexadecimal integer input.