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SAP Sybase SQL Anywhere 16.0 » Context-Sensitive Help » MobiLink plug-in help » Mappings tab » Mappings: Details


Download Deletes tab

The Download Deletes tab applies if the download type chosen on the Download Type tab is not Custom.

This tab allows you to control whether deletions on the consolidated database are downloaded to remotes and how the information about those deletes is stored in the consolidated database. The Download Deletes tab shows the following information for the selected table:

  • Download Deletes   When this checkbox is selected, data that is deleted on the consolidated database is deleted on the remote databases.

    If you are using snapshot downloads and this option is selected, all existing rows in the remote database are deleted before the downloaded rows are added.

    If you are using timestamp-based synchronization and this option is selected, the deletions on the consolidated database need to be recorded. There are two ways of doing this: using shadow tables (the default), or using logical deletes.

    This option cannot be selected if the download type is Custom. In that case, you must write your own download_delete_cursor script. You can do this on the Events tab.

    • Use shadow table to record deletions   Select this option to use shadow tables to track deletes in the consolidated database.

      A shadow table is a separate table that contains the primary key columns of the table being synchronized along with a timestamp that indicates the time when the row was deleted. When a row is deleted from the consolidated table, a corresponding row is added to the shadow table to record the deletion so that it can be downloaded to remote databases. Shadow tables are created with the same owner as the consolidated table.

      • Timestamp column name   Specifies the name of the TIMESTAMP column. The default Timestamp column name is last_modified.

    • Use logical deletes   Select this option to use logical deletes in the consolidated database to track deletions in the consolidated database. Logical deletes use a status column to keep track of whether rows are valid. The following options specify how the status column tracks deletes:

      • Column name   Specifies the name of the column that is used to indicate if a row has been deleted. This column is added if it is not already present. The default name is deleted.

      • Value if row deleted   Specifies the value that is generated when a row is deleted. The default is Y.

      • Value if row not deleted   Specifies the value that is generated when a row is not deleted. The default is N.

 See also