(DDL) and a Data Manipulation Language (DML). D4 also has an Imperative Language for procedural code. Data Definition Language The DDL for Dataphor bears many similarities to other DBMSs, but with an obviously Pascal-like twist. Many of the allowed DDL operations, like constraints, allow relational declarative statements to be used, which many believe is superior to the procedural style operations used in SQL. Data Manipulation Language The DML syntax at first glance may appear to be similar to SQLs syntax, but because of D4's closer ties to relational algebra, the syntax has a cleaner definition, and most users greatly prefer it over SQL. Imperative language The Imperative Language in D4 is remarkably similar to Pascal in many respects. The largest distinction being that D4 also allows DDL and DML statements to be run in regular procedural code. History D4 was named after the similar-sounding Dataphor, the system that uses the language. It was some time after these names were decided that its creators discovered Tutorial D, and the coincidence it had with that name. Since discovering Tutorial D and The Third Manifesto, the creators have used The Third Manifesto as a guide in making Dataphor and D4. Since then, Hugh Darwen has referred to D4, as a notable project in his talk entitled The Askew Wall. Federated Storage Engine While Dataphor has a storage engine of its own, it can also connect to other RDBMSes, and use them as a storage engine. Dataphor can use the following DBMSes as storage engines: Microsoft SQL Server Oracle IBM Db2 and others Dataphor can access Oracle, IBM Db2, Microsoft SQL Server, PostgreSQL, MySQL and any other storage engine with a single unified language. Frontend Library The Dataphor Frontend library provides for the delivery of dynamically derived, or pre-designed static forms. The library is exposed as a standard set of D4 functions (called operators in D4) such as Form ('', '') and Derive ('', ''). The resulting forms are described in an XML dialect called a Dataphor Form Document (DFD). The form description is high-level, consisting of a general description of the user interface aspects as they apply independent of client platform. Dataphoria IDE Dataphoria is an integrated development environment for: Editing D4 Ad hoc execution of D4 Creating, Editing, and Customizing (inherited) forms Managing libraries Analyzing execution plans Windows Client The Dataphor Windows Client is a thin client in the sense that it