Preface

LOCUS INGRES SQL Version 1.0 supercedes the INGRES QUEL version. SQL is an acronym for Structured Query Language which is the ANSI database query language. The QUEL query language is a proprietary product of INGRES. LOCUS now translates the user's request into SQL to access database data instead of QUEL. The most significant changes in the user interface include: 1) an initial menu to describe the database and tables to be accessed, 2) a substantially rewritten EDIT which lets you edit any of those tables, and 3) the specification of NODATA. In the databases themselves SQL standard nulls are used instead of the previous LOCUS internal representation. To use constraints involving nulls, the syntax is now: IS NULL and IS NOT NULL. Sample constraints are "IP IS NOT NULL" and "COMMENT IS NULL". Note that you must enclose these in quotes in LOCUS because they have embedded spaces. New features are:

Multiple key joins

You can now join on SHOT, TIME, and RADIUS for example.

Arbitrary joins

You can join three or more tables on different keys, for example: A.SHOT=B.SHOT and B.RADIUS=C.RADIUS.

Duplicate names

You can access parameters and expressions that appear in more than one table.

Improved handling of NULLS

Nulls can be used in constraints like "QEI IS NULL or QEI=0".

BETWEEN

The SQL syntax "IP BETWEEN 1.5 AND 3.5" can be used in specifying symbols and constraints.

Speedy symbols

Symbol constraints of the form "COLUMN OPERATOR CONSTANT" and "COLUMN BETWEEN CONSTANT1 AND CONSTANT2" are OR'd together and gotten in a single retrieve.

Improved table editing

EDIT lets you access any of the tables in your session.

SQL commands

You can execute arbitrary SQL commands from the main options menu, e.g., DROP TABLE XTESCALNEW or SELECT AVG(NE) FROM TESCAL.