Technical Reference Manual - InduSoft

Background Tasks
The header of the database worksheet is configured as follows:
• Description field: Enter a description of the worksheet, for documentation purposes.
• Status field: Enter the name of a numeric tag that will receive status codes for database operations during
runtime:
Status codes for external database operations
Status Code
Description
4 Result set is empty
3 Cursor released and query successfully closed
2 Beginning of result set reached, usually while moving cursor to previous row
1 End of result set reached, usually while moving cursor to next row
0 No errors; status normal
-1 Error while connecting to specified database (see Connection below)
-2 Error while selecting result set
-3 Error while moving cursor to next row (see Next trigger below)
-4 Error while moving cursor to previous row (see Previous trigger below)
-5 Error while closing the query (see Close Query trigger below)
-6 Error while inserting rows in result set (see Insert trigger below)
-7 Error while updating result set (see Update trigger below)
-8 Error while deleting result set (see Delete trigger below)
• Completed field: Enter the name of a numeric tag that will be toggled when database commands are
successfully executed.
• Error Message field: Enter the name of a string tag that will receive detailed error messages, if errors occur
during runtime.
• Connection combo-box: Click to select a connection to the target database. All available connections are
listed, as configured with the Database Connection dialog described above.
• Type combo-box: Click to specify how the result set will be selected for the worksheet:
• Table: Enter a table name and an optional filter condition. (The filter condition is equivalent to the SQL
"Where" clause.) All rows of the table that match the filter condition are selected.
• SQL: Enter a custom SQL "Select" statement.
Note: For Table, Condition and SQL Statement, you can enter the names of project tags that contain
the desired information. This lets you programmatically change the selection during runtime.
However, tag names must be enclosed in curly brackets ({}) to distinguish them from literal
strings. Also, you must release an existing selection before you open a new one; see Close Query
below.
• Cursor Triggers area…
• Select field: Enter any tag; when the value of the tag changes, a new cursor opens the first row of the
result set and copies those values to the tags configured in the worksheet body.
• Next field: Enter any tag; when the value of the tag changes, the cursor moves to the next row of the
result set and copies those values to the tags configured in the worksheet body.
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