Welcome to the Quest Error Manager Utility Community!
This community is the offical headquarters for the Quest
Error Manager Utility (QEM).
The Quest Error Manager (QEM) is a framework that will help
you standardize the management of errors in a PL/SQL-based application. With
QEM, you can register, raise and report on errors through an API that makes it
easy for all developers to perform error management in the same way, with a
minimum amount of effort. Error information is logged into the instance (general
information about the error) and context (application-specific name-value pairs)
tables. You should install QEM separately for each application you build. QEM
also offers programs that: substitute for DBMS_OUTPUT.PUT_LINE; trace execution
of your application; and assert or validate assumptions.
The Error Manager helps you in these two areas:
1. Error definition and management
Use the q$error_manager package to raise, handle and log errors. Rather than
write low-level error logic yourself, you simply call the appropriate
program in the package API. The Error Manager will then write error
information to a set of error tables. You can then extract this information
and pass it back to the user (front-end environment) or query the tables to
help diagnose the cause of the problem.
2. Runtime execution tracing
The Quest Error Manager offers a single package to help you trace the
execution of your application. With q$error_manager, you can
- Write to table or screen: Write trace
information out to the q$log table (using the autonomous transaction
feature, to ensure that the trace is saved without affecting your
application transaction) or to the DBMS_OUTPUT buffer.
- Selectively turn on and off tracing through
calls to the q$error_manager procedures. You can in this way set tracing for
a given application test run, or you can build your own runtime interface to
these programs in your application, as we did in The Quest Error Manager.
- Trace execution of code by a context string,
and then also include strings, numbers, dates or Boolean values. You can
also minimize the overhead of tracing by checking to see if trace is enabled
before calling the trace program.
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Installing the Quest Error Manager
Download and unzip the qem.zip file into your directory of choice (for
example, c:\QEM).
You can choose to install the Error Manager into your application schema, or
create a new schema for these objects. If you want to be able to execute
Error Manager from other schemas, you will need to create the appropriate
public or private synonyms. We do not provide a script to do this.
Run the qem$install.sql script from your chosen schema to install the nine
database objects associated with the Error Manager:
- Tables: q$error_context,
q$error_instance,q$error,q$log
and their associated sequences
The q$error_manager package
You can integrate this script into your own application install scripts, if
you choose.
Removing the Quest Error Manager
Run the qem$uninstall.sql script from the schema in which you installed the
Error Manager to remove all the database objects associated with the Error
Manager.
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