# SQL syntax

SQL syntax is presented in modified BNF notation.

The meta-symbols of BNF are:

Symbol | Meaning
--- | ---
`|` | or. Choose one of the items
`[ ]` | Enclose optional items.
`*` | Flags items that you can repeat 0 or more times. Has a special meaning in some SQL statements.
`{ }` | Groups items so that they can be marked with one of the other symbols, i.e. [ ], |, or *.
`( ) . ,` | Other punctuation that is part of the syntax.

An example of how SQL syntax is presented:

    CREATE [ UNIQUE ] INDEX IndexName
      ON TableName ( SimpleColumnName [ , SimpleColumnName ] * )

Command-line syntax for running Java programs and utilities (as well as examples) always begins with the word java:

    java org.apache.derby.tools.ij

This documentation attempts to be JVM neutral, but any command line examples or syntax using JVM specific references should be verified with your JVM documentation.

Parent topic: Documentation conventions