Extended SQL change definition language for a computer database system

• US 6,115,704 A
• Filed: 05/09/1994
• Issued: 09/05/2000
• Est. Priority Date: 09/27/1991
• Status: Expired due to Term

• Current Assignee: BMC Software Incorporated (KKR & Co., Inc.)
• Original Assignee: BMC Software Incorporated (KKR & Co., Inc.)
• Inventors: Olson, Jack Edward, Elliott, Linda Carolyn
• Primary Examiner(s): Fetting, Anton W.
• Application Number:
  US08/239,942
• Time in Patent Office: 2,311 Days
• Field of Search: 395/650, 395/700
• US Class Current: 1/1
• CPC Class Codes: G06F 16/284 Relational databases
• CPC Class Codes: Y10S 707/99933 Query processing, i.e. searching

Abstract

A change definition language (CDL) serves as an extension of (and in the general format of) the structured query language known as SQL. The change definition language allows all important alterations to be described, as changes to an existing definition, for example, and may be used by all phases of the development cycle. The CDL statements do not make the changes directly in the catalog, but instead work through SQL and another intermediate mechanism such as DB2 ALTER tailored to make changes using SQL. The changes expressed in CDL may be migrated to downstream phases and fed back to earlier phases by use of a batch of change statements expressed in CDL.

Claims

1. A method of altering an existing data structure in a database system,

said existing data structure including a plurality of related tables of columns and rows of data values and further including one or more indexes for said related tables to provide a relational database, said existing data structure being defined by a catalog data structure including tables of tables and indexes, said method comprising the steps of:

a) receiving a change indication signal,

1) said change indication signal encoding one or more statements conforming to a change definition language that is a superset of a SQL structured query language,

2) said change definition language including a plurality of available statements for changing at least one of A) a data specification of a column, B) an owner of a table or an index, and C) a name of a column or an index,

3) said one or more statements specifying one or more requested changes to be made in the existing data structure;

b) testing whether said one or more requested changes can be made in the existing data structure; and

c) if said changes can be made in said existing data structure, then making said changes, or else signaling an error.

2. A method executed by a computer system of making changes in a data description catalog of a DB2 database implemented on said computer system, comprising the steps of:

a) receiving a list of change statements describing said changes, said change statements being selected from a library of change statements in the format of a change description language constituting a superset of an SQL structured query language, including statements for changing, in said data description catalog;

a data specification of a column,

the owner of a table, an index or a view,

the name of a column, an index or a view;

b) generating from said list a set of changes to said data description catalog, said set of changes being in an SQL data description language for said database; and

c) invoking execution of an SQL routine to read and execute said set of changes.