Database is where an external database system is defined. It can be any ODBC supported SQL database. For instance Microsoft SQL 2005 Express edition, which is free for 4 GB of data storage.
| Parameter | Description |
|---|---|
| name | Any unique name to be referred in Tag or Alarm table. |
| description | Additional description. |
| Connection String |
This is a working example for Microsoft SQL 2005 express edition. In this database connection string, note that the DATABASE parameter need to be modified according to the database created earlier using database creation wizard. For instance if a database called my_job, meaning the parameter need to be written as "DATABASE=my_job". Note that for readability reason, the sample was split into lines, in actual scenario, enter the string in one line only.
Provider=MSDASQL.1; Extended Properties="DRIVER=SQL Native Client; SERVER=<COMPUTER_NAME>SQLEXPRESS; DATABASE=my_job; trusted_connection=yes"; 
Clicking browse button shall launch the Data Link Properties which could on the string entered. |
| Log | Define how frequent a data will be logged. |
| Purge | Define how frequent the server will perform purging sequence. |
| Purge Count | Define how long or how big a database shall be kept. For instance, a value of 90 means data will be stored for 90 days only. Based on FIFO logic, the 91st day old data will be deleted during purging process. |
| Purge Type | Always fixed to 'day count' only. System works on First In First Out basis, i.e. old data will be deleted first. |
![[Tip]](images/tip.png)
Tip
Note that most of the entries will be automatically entered when a project is created. Most of the time, only the logging frequency need to be customized.