next up previous contents index
Next: Running LOCUS Up: An Introduction to Using Previous: The Database

Parameter and Expression Tables

Tables that contain rows of parameter values are called parameter tables . A column is another name for a parameter in a parameter table. LOCUS also supports expression tables  which are tables that contain expressions and their names. These expressions can then be used like parameters in most of the LOCUS programs provided that the expression can be defined in terms of the parameters in the parameter tables that you are currently using. Expression tables are optional. An alias  is an abbreviation for a table name which allows you to access duplicate names succinctly.

A database  is a collection of tables  which can be connected. A table is a single table or a previously defined view  of one or more tables in the same database. Only tables within the same database can be looked at together. If you intend to access data from different tables, then the tables must be in the same database.

The name of a database  or table can be up to 24 characters long; parameters and expression names can be up to 32 characters long. All names must begin with a letter and can contain A-Z, 0-9, and underscore. (Do not use any INGRES keywords, e.g., abs, or, or tid  as the name of a parameter or expression.) You can have up to 300 parameters in any table. Expressions  can be up to 132 characters long.

Marilee Thompson
Fri Jul 11 17:05:56 EDT 1997