DP4 SQL Engine Reference

This part of the DP4 SQL guide describes the SQL language as implemented by the DP4 SQL Engine. This determines the SQL statements that are accepted by both the DP4 SQL product, and the ODBC Drivers and DP4 DDE products.

If you are already familiar with another vendor's implementation of the SQL language, you may find it useful to review the information in Comparison with Other SQL Implementations.

For a guide to standard SQL, refer to A Guide to the SQL Standard by C. J. Date, or a similar work. (We use the Reference Manual published by Osborne, in conjunction with Microsoft ODBCODBC documentation, as well as manuals for products such as Oracle and Sybase as a basis for deciding on the correct parsing and interpretation of SQL statements.)

If you are using the DP4 ODBC driver via a program such as Microsoft Access you should be aware that the SQL it shows you may be significantly different from the SQL it submits to DP4. This can be a cause of problems, as the program may generate parse errors itself for SQL that would in fact be acceptable to DP4.

The following pages describe the language accepted by the DP4 SQL Engine.

• SQL Statements introduces the various SQL statements:
  • The SELECT statement
  • The INSERT statement
  • The UPDATE statement
  • The DELETE statement
  • The COMMIT WORK and ROLLBACK WORK statements
• SQL Notation describes the low-level syntax for identifiers, literals and so on, including :
  • Date/Time Arithmetic
  • SQL Trigraphs
• SQL Implementation describes how the various SQL statements are executed on the DP4 database. This section contains information which may be useful in decding how best to express a SQL query.
• Comparison with Other SQL Implementations