An Indexed Column is a column in the database that can be accessed more quickly than other columns (there are internal mechanisms that allow these columns to be searched more easily than the other columns).
There are a limited number of Index Columns, and the Index Columns that are available vary according to the type of table that is being searched. The following table shows the Index Columns that are available for each type of database table:
|
Table Type |
Unique Indices |
Non-Unique Indices |
|---|---|---|
|
Object |
Id, FullName |
ParentGroupId, Search Keys |
|
Aggregate |
- |
Id |
|
Alarm Condition |
- |
Id |
|
Event Journal |
RecordId |
Id, Source, FileId |
|
Point Historic |
RecordId |
Id |
|
Processed Historic |
RecordId |
Id |
|
Forecast Historic |
RecordId |
Id |
|
Data Table |
- |
As configured |
|
Data Grid |
- |
- |
| Data Set | - | - |
| Alarm Summary |
ActiveTime InactiveTime |
- |
The columns are listed in cost order, for example, for the Object table, the Id column has a lower cost than the FullName column (and so can be searched more efficiently than the FullName column).
The values in the rows of an Index Column are referred to as index values.