| #### Developing Time-Oriented Database Applications in SQL Richard T. Snodgrass |

### Retaining A Tracking Log

## Contents

An Audit Trail specifies the sequence of modifications that have been applied to a single table, the audited table. The audit trail allows the audited table to be reconstructed as of any time in the past. It can be used to undo any inadvertent modifications, or to restore the audited table to a previous consistent state.

    Implementation Details - Implementation characteristics that may be specific to a particular DBMS.
    Defining an Audit Trail - Definition of the audit trail table.
    Queries and Modifications - Reconstructing the table at any day in the past.
    Permitting Insertions - Allow an Insert trigger as well.
    Backlogs - Include explicitly the modification operator.
    Using After Images Consistently - Simplification of the reconstruction algorithm.
    Running Examples - Actual source code which can be executed.

# Implementation Details

  IBM DB2 Universal Server
  Oracle8 Server
  Sybase SQL Server
  UniSQL

# Defining an Audit Trial

> IBM DB2 Universal Server
> Oracle8 Server
> Sybase SQL Server
> UniSQL

# Queries and Modifications

> IBM DB2 Universal Server
> Oracle8 Server
> Sybase SQL Server
> UniSQL

# Permitting Insertions

> IBM DB2 Universal Server
> Oracle8 Server
> Sybase SQL Server
> UniSQL

# Backlogs

  IBM DB2 Universal Server
  Oracle8 Server
  Sybase SQL Server
  UniSQL

# Using After Images Consistently

  IBM DB2 Universal Server
  Oracle8 Server
  Sybase SQL Server
  UniSQL

# Running Examples

> Sybase SQL Server
> Oracle8 Server
> UniSQL

HTML Credits

Jose Alvin G. Gendrano, Department of Computer Science, University of Arizona (jag@cs.arizona.edu)
Rachana R. Shah, Department of Computer Science, University of Arizona (rachana@cs.arizona.edu)
Jian Yang, Department of Computer Science, University of Arizona (yangjian@cs.arizona.edu)
April 27, 1999 (Last Update)