Details of the key field update mechanism

The key field update allows you to update only certain fields of existing records.
The key fields are used to designate the records to be modified in the host table using the equivalent item combinations in the data from the compartment.

An option is provided to add records from the questionnaire compartment that have no equivalent in the database.

The key fields are most commonly a primary or secondary key (actual or potential unique index) for the data in the host table.

The data from the compartment is first reduced to the item combinations of the key fields and the first values found for the other fields. This data is then integrated into the host table.

The logic of the update on key fields is that of a column by column update.

When Calame questionnaires do not add or remove records from the initial data, it is always preferable to use key field updating.

Example (key axes: KeyAxis1, KeyAxis2)