By default, Data Mart stores a single point in time snapshot of your business data based on a single source rule. This data is periodically refreshed from Eagle's data warehouse during the submit process. See Submit Models as Ad Hoc for details.

You can create multiple snapshots of your Mart data, each one using data sources that are relevant to one or more business purposes. For example, suppose your organization runs a pension fund. You can create a snapshot that looks at fund activity from a custodian's view point and another snapshot that looks at fund activity from a manager's view point. You can also use snapshots to report on the same portfolios in different accounting basis. These different perspectives must exist as different data sources in your data warehouse.

Each snapshot can also save your data at a specific time, allowing you to make accurate comparisons between different intra-day time periods. For example, you can populate your Mart three times a day and save a snapshot of that business data as of the morning, mid-day, and end-of-day.

Once you have populated the Mart tables with a snapshot, your reporting tool can access the data. The Fund Master table stores the SNAPSHOT_ID field that contains the name you assign to your snapshot. This field combines with the ENTITY_ID and EFFECTIVE_DATE fields to determine the DMART_FUND_ID field that links together other Data Mart tables of the same fund and date. SQL queries that select a particular entity and date can also select the SNAPSHOT_ID. Note that if you have set up reports based upon SQL statements written before you added snapshots, you have to change them after you add snapshots to select a SNAPSHOT_ID of DEFAULT.

Since the DMART_FUND_ID field does not appear in the Security Details and Issuer Details tables, those two tables contain the SNAPSHOT_ID as a key field. If your organization does not use snapshots, there is no need to change existing queries, because all of your DATA_MART_FUND_ID values point to the same default snapshot, making it unnecessary to reference the SNAPSHOT_ID in your SQL queries.

Add a Snapshot

To add a snapshot:

1. In Reporting Center, from the left navigation, select Reporting Tools > Datamart > Manage Marts > Data Mart.
   You see the Data Mart workspace.
2. Click the Snapshots link.
   You see the Snapshots dialog box. 
3. Click Add Snapshot.
   You see the Snapshot Definition dialog box as shown in the following figure.
4. In the Name box, provide the name up to 10 characters for the snapshot. This name appears in the FUND_MASTER table as the Snapshot ID after you build data for the snapshot.
5. In the Description box, provide a description about the snapshot.
6. Click Source Rule dropdown to determine the source rule to use.
   Select <default> if you want to use the source rule set up in the Configuration tab. If you want to use a different source rule to support another perspective on your data, choose another source rule from the list.
7. Click Business Calendar dropdown to determine the business calendar to use when you submit the Business Dates model for this snapshot to update the Business Dates table.
8. In the Comments box, provide a descriptive comments about the snapshot, if any.
9. Complete the fields on the Snapshot Definition dialog box and click OK to save your changes.