Tables
The data is split into tables in a DB. The number of tables used in a DB is only limited by the available memory space. Tables can only be created in a DB that already exists and is defined for the DBLogger.
The DBLogger manages two table types in the DBs:
Internal tables
These are used for internal administration of the data. These tables are created and updated automatically as required.
IS_Tables: contains one column; all the user-defined tables from the type StandardHistory employed in the DB, are listed here.
Column in the table:
| Column name | Type | Max. length | Indexed | Content |
|---|---|---|---|---|
| Tables | String | 100 | yes | Table name |
IS_Tables_Flex: contains one column; all the user-defined tables from the type FlexTables employed in the DB, are listed here.
Column in the table:
| Column name | Type | Max. length | Indexed | Content |
|---|---|---|---|---|
| Tables | String | 100 | yes | Table name |
When a new table is created, a new entry is written in this table; when a user-defined table is deleted, its entry in this table is also deleted.
This table is NOT updated when table data points are created manually.
IS_Description: Extra information on all data point elements transferred by the DBLogger to a relational database is saved here. Whilst useful data such as values, status bits etc. are saved relatively frequently (when they change, periodically etc.), this additional information is transferred just once by the DBLogger. This table exists just once for each DB.
Columns in the table:
| Column name | Type | Max. length | Indexed | Content |
|---|---|---|---|---|
| DPE | String | 255 | yes | DPE name |
| Alias | String | 255 | yes | DPE alias |
| Langtext | String | 255 | no | DPE description |
| Einheit | String | 255 | no | DPE units |
| Format | String | 10 | no | Format (for example, "%6.2f") |
| Datentyp | String | 5 | no | BIT|UINT|INT|FLOAT |
| Bereich_Min | Float | - | no | WinCC OA value range minimum |
| Bereich_Max | Float | - | no | WinCC OA value range maximum |
IS_ + Name of the table of type "FlexTables" + _Description: This table saves further information on tables of the type "FlexTables", which exist in the database. This table exists once for each "FlexTables" table defined in the database.
Columns in the table:
| Column name | Type | Max. length | Indexed | Content |
|---|---|---|---|---|
| Name | String | 50 | no | Column name |
| Width | Long Int | - | no | Width |
| DPE | String | 255 | no | DPE name |
| Type | String | 10 | no | Field type: String|Date|Double|Long |
| IsAnIndex | Long Int | - | no | Indexed/not indexed |
This table is updated when tables are configured and whenever DBLogger is started. The data points that are no longer included in current parameter settings are NOT deleted because tables may still contain values from DPEs that existed before.
IS_Alive: A monitoring function writes the current time in this table at predefined time intervals in order to be able to analyze any breaks in communication etc. if necessary.
Columns in the table:
| Column name | Type | Max. length | Indexed | Content |
|---|---|---|---|---|
| Zeit | Date/Time | - | no | Current time |
| Host | String | 25 | no | Host name of the computer, which writes into the DB (in case of redundancy). |
| Status | String | 7 | no | Status text (in case of redundancy the active/passive host is shown in this column when starting resp. after switching). |
Whenever the DBLogger is started, two lines are written to this table:
-
current time + "ON" and
-
current time + "OFF".
After this the last line is regularly updated with the current time.
User-defined tables
"StandardHistory" data model
These tables contain the useful data transferred from WinCC OA. This predefined data model can not be modified by the user. You can use one table of the data model StandardHistory with several archive groups.
Columns in the table:
| Column name | Type | Max. length | Indexed | Content |
|---|---|---|---|---|
| DPE | String | 255 | yes | DPE name or alias |
| Zeit | Date/Time | - | yes | Source time |
| Wert | Float | - | no | Original value |
| Status | Long Int | - | no | Original status |
This table can only be used for the data types bool, uint, int, float.
"FlexTables" data model
The data model FlexTables was also implemented to save useful data from WinCC OA. But the difference is the flexible definition of columns. Each column (except the first=Time column) is assigned to a data point element in WinCC OA. The number of columns, the assignment of DPE's, types and transfer parameter are defined for each table. These settings are directly saved in the table type DP. Type=1 is FlexTables. You can use one table of the data model FlexTables with one archive group.
Columns in the table:
| Column name | Type | Max. length | Indexed | Content |
|---|---|---|---|---|
| Zeit | Date/Time | - | no | Source time |
| Name1 | Float | - | no | Online value |
| Name2 | Float | - | no | Online value |
| Name3 | Float | - | no | Online value |
| Name4 | Float | - | no | Online value |
| ... | ... | ... | ... | ... |
This table can be used for the data types bool, uint, int, float, string, char, time, bit32.
