The Join Hierarchy in Query Resolution

Sybase IQ can use the same join index to resolve a query that involves the full join relationship specified in the join index, or a query that involves any contiguous subset of that relationship. You do not have to create separate join indexes for the subset relationships.

For example, assume that join index ABCDEF joins the tables illustrated in the Hierarchy of a join relationship figure. Sybase IQ can use join index ABCDEF to resolve any queries that involve:

The entire relationship
Table A to Table D
Table A to Table D to Table F
Table B to Table D
Table B to Table D to Table F
Table D to Table F
Table C to Table E
Table E to Table F
Table C to Table E to Table F

However, Sybase IQ cannot use join index ABCDEF to resolve queries against, for example, Table E to Table D.

One-to-Many Relationship
In a one-to-many join relationship, one row in one table potentially matches with one or more rows in another table, and there is not more than one row in the first table that matches with the same row(s) in the second table.

Parent topic: Using Join Indexes

Related concepts

Join Hierarchy Overview

Relationships in Join Indexes

Steps in Creating a Join Index