A Database Assembling is always performed when an E3Playback is activated. Information about database structure collected during this assembling process is kept while the playback section is active. The steps of a database assembling process can be summarized as:

1.Enumerate all database tables.

2.Check which one of these tables have the corresponding _Fields table. For example, when Elipse E3 generates an alarm table named E3Alarms, it also generates a table with a description of fields on the alarm table (E3Alarm_Fields).

3.Analyze fields from each table, as well as the contents of its corresponding _Fields table to determine its table type. An E3Playback recognizes three types of tables:

•Storage: This table must have E3TimeStamp, FieldID, Quality, and FieldValue fields

•Alarms: This table must have EventTime (or EventTimeDbl), ConditionActive, Acked, AckRequired, and FullAlarmSourceName fields

•Historic: This table must have E3TimeStamp field, and must not have been recognized as a Storage or Alarms table

4.If this table is a Storage-type, the _Fields table is scanned to determine which Tags are stored on it. A Tag's path is determined by table's FieldName field. The field that provides timestamp data is always E3TimeStamp. Each Storage can have up to three data tables, one for each data type:

•Strings: Table name is <Table>_String

•Bit/Digital: Table name is <Table>_Bit

•Double/Analog: Table name is <Table>

5.If this table is a Historic-type, the _Fields table is scanned to determine which Tags are stored on it. A Tag's path on this case is determined by table's FieldSource field. The field that provides timestamp data is always E3TimeStamp.

6.If this table is an Alarm-type, the _Fields table is scanned to determine user's alarm field names, if they exist. The field that provides timestamp data is EventTime, optionally combined with EventTimeMS field, if it exists, or EventTimeDbl field. This last one has priority because it represents milliseconds with higher precision.

7.After all data tables and Tag paths are detected, a simple query is then performed on each one of these tables to determine the oldest and newest date stored on this table. This allows determining date intervals where playback is allowed.