Tag Tables are primarily used for maintenance of data source specific tag values.
These types of tables are characterised by a single TagValueID column which is also a primary key.
A data source tag table can collect data in various ways: (Tag Type field)
- All Values (Automatically fetch all values) - Typically used if one wants automatically generated UNION ALL statements for each value instance.
- Multiple Values (Allow user to select values from a list box and save as multiple values) - Typically used if one wants automatically generated UNION ALL statements for each value instance. Additionally this type allows the user to select the values initially from list box; leaving the table in an editable state after user has selected first time. This is the default setting if type is not specified.
- Number List (Values saved as a comma separated number list) - Typically used if one wants a comma separated list of values for use in WHERE ... IN (...)-clauses.
- Single Value (Automatically select a single value) - Stores a single value in a single row. This is a commonly used tag type.
- String List (Values saved as a comma separated string list) - Typically used if one wants a comma separated list of values for use in WHERE ... IN (...)-clauses.
The Usage link button performs a lookup and display a list of data source tables where the tag is used. (Note! The list displays one hit per data source table consumer. So if the tag is used in two contexts (i.e. Table Name and Reload Filter), only one of the contexts will be listed)