Combining Index Types; Adaptive Server Iq Index Types - Sybase Adaptive Server IQ 12.4.2 Administration And Performance Manual

Adaptive Server IQ index types

Combining index types

Adaptive Server IQ index types
144
• data with more than 255 bytes
VARCHAR
indexes do not allow
HNG
All other data types are supported in all index types.
If you try to create an index on a column that contains
than 255 bytes, you get this error message:
An index cannot be created on a varchar column greater
than 255 characters.
If a column is going to be used in more than one type of query, multiple column
index types might be appropriate. The following table shows which index types
make good combinations.
Table 4-4: Mix of valid indexes
Add Index
Existing Index HG
HG -
HNG 1
LF 2
1 = A reasonable combination
2 = An unlikely combination
The High_Group index in Adaptive Server IQ Version 12.0 differs from
Note
earlier versions. For some columns you may want both High_Group and
High_Non_Group; previously, it did not make sense to have both.
This section explores in depth the reasons you might use each of the column
index types.
, , or
FLOAT REAL DOUBLE
HNG
1
-
1
data.
data greater
VARCHAR
LF
2
1
-