CHAPTER 4 Adaptive Server IQ Indexes
153
Adaptive Server IQ join hierarchies have one table at the top of the tree where
the join ends. This table, known as the top table, does not connect to any other
tables, although other tables connect to it. The top table always represents the
“many” side in a one-to-many relationship.
Depending on the complexity of the join, there could be a straight line of tables
down to the bottom of the tree and the beginning of the join, or there could be
many branches off to the side as you move down the tree. The following figure
shows a join hierarchy with two branches.
Figure 4-1: Hierarchy of a join relationship
In a join hierarchy:
•
A table can occur only once
•
A table can only connect out once (one arrow leaving it)
•
All tables must be connected
Columns in the join index
Suppose that you joined Tables A through E in a join index called
ABCDE
. If
each table has two columns of data, expect the join index to have a total of
fourteen columns. Adaptive Server IQ creates an additional column, the
ROWID
column, for each of the joined tables except the top table. In this case,
there are ten columns (two from each of the five tables), plus four
ROWID
columns.
You can use the
NOTIFY
option of the
LOAD TABLE
or
INSERT
statement to
receive notification messages when you insert into a column index. In these
messages, the name of each column in a join index, including the
ROWID
column, is identified.
Summary of Contents for Adaptive Server IQ 12.4.2
Page 1: ...Administration and Performance Guide Adaptive Server IQ 12 4 2 ...
Page 16: ...xvi ...
Page 20: ...Related documents xx ...
Page 40: ...Compatibility with earlier versions 20 ...
Page 118: ...Troubleshooting startup shutdown and connections 98 ...
Page 248: ...Importing data by replication 228 ...
Page 306: ...Integrity rules in the system tables 286 ...
Page 334: ...Cursors in transactions 314 ...
Page 396: ...Users and permissions in the system tables 376 ...
Page 438: ...Determining your data backup and recovery strategy 418 ...
Page 484: ...Network performance 464 ...
Page 500: ...System utilities to monitor CPU use 480 ...
Page 514: ...Characteristics of Open Client and jConnect connections 494 ...
Page 536: ...Index 516 ...