QuerySet/Query Validation

When the Database Connector loads the configuration.xml, validation for all the statements, querysets and queries in the configuration.xml file is performed. Validation results are shown when you browse the status URL and appropriate error messages are displayed in the browser.

This provides an easy way to find all syntactic or schema related issues such as:

• If a Retrieve operation or template is not properly defined in the configuration.xml
• If a query is empty or disabled
• Invalid Query statement

• Invalid credentials

• Incomplete xml element

• Database URL parameter is not present

You may also see warnings for valid queries. For example, it is recommended that the useServerPrepStmts=true to a MySQL connection url to improve statement validation. If this parameter is missing, you may see a warning message to add it.    
If the configuration.xml file is not found, the status URL will report it immediately. See the Common Problems section for some examples.

When the Database Connector is running, it is constantly looking for configuration.xml file changes. If you have to make a change to a query in your configuration.xml to fix a reported issue, you Do not have to restart after you make the correction.The connector will pick up the changes.

The image shows the the queryset/query validation and other entries that you will see in the database-connector.YYYY-MM-DD.log file when the connector loads.

REST parameters for the test URL

It is very helpful to first test your queries by entering the query URL directly into your web browser and verify that the data resultset returned to your browser as a web page is as you expect.

Once you have the Database Connector working with your database you can test your query by copying a test URL into your browser.

The URL to the database connector has the following REST parameters:

http://<host>:<port>/database/<queryset-name>/<query-name>

Where:

• <host> - the URL for the web server on which you deployed database.war.
• <port> - port where the container is listening for http requests. This defaults to 8082 if the database connector was deployed in the  tomcat bundle or port 8081 if you are running the Database Connector in Standalone mode.
• <queryset name> - queryset name defined in the database connector configuration file.
• <query name> – query name  defined in the database connector configuration file.
  
  

Logfiles

The Database Connector uses SLF4J with logback, which is the same logging infrastructure used in  .

Log MDC entries for configuration path, the querySet name, the query name, correlation.id, tenant id, subject.id. These will be captured when processing client requests.

11:37:25.394 |-WARN  [http-nio-8082-exec-8] [c.f.c.d.s.MetaDataService] [mycompany ] [26d27ffe-1213-4c82-890b-cdc1a2e00e87 ] [  ] - Could not find retrieve operation for query STUDENT/addStudent. Skipping ...
11:37:27.186 |-ERROR [http-nio-8082-exec-8] [    c.f.c.d.QueryResource] [mycompany ] [26d27ffe-1213-4c82-890b-cdc1a2e00e87 ] [  ] - Error processing request for querySet STUDENT

Exceptions are properly logged with their stacktraces. This makes it easier to diagnose errors, which sometimes are frevvo/DBConnector specific and sometimes database specific.

All JDBC statements are logged in the DEBUG logging level. This includes the actual SQL statement used, the actual arguments, the number or rows returned and whether it was successful.

There are different logfiles for the Standalone and tomcat bundle installations.

Standalone mode

1. Four logfiles are created in the \database\database-connector-2.5.2\logs directory:
   
   1. DbConnector.err.log - there is no content in this log at this time
   2. DbConnector.out.log - database connector standard out file. You can see the version of the database connector that is running in this file.
   3. DbConnector.wrapper.log - Date/Times of connector starts/stops when the Database Connector is running as a service.
   4. database-connector.YYYY-MM-DD.log - This is the main logfile for the Database Connector. You can see the results of the queryset/queries validation and output error messages in this file. This log will rotate daily.
      
2.  derby.log - this logfile contains information about the built-in Derby databases that come with the DB Connector
   
   

Tomcat bundle

When debugging database queries refer to output error messages in <frevvo-home>\tomcat\logs\database-connector.YYYY-MM-DD.log. This log will rotate daily.

Log levels for the DB Connector log are controlled by profiles. The prod profile is the default.

• prod - connector log level will be set to INFO for production environments. When this profile is loaded, log levels are set to:

  • logging.level.=WARN 

  • logging.level.com.frevvo=INFO

To change the log level to DEBUG, add a property to the <frevvo-home>\tomcat\conf\dbconnector.properties file to load the dev profile.

spring.profiles.active=dev

When this profile is loaded:

• dev - connector log level will be set to DEBUG , Log levels are set to
  • logging.level.=INFO
    
  • logging.level.com.frevvo=DEBUG

Common Problems

Live Forms tomcat running on non-default port

If you have configured your tomcat in <frevvo-home>/tomcat/conf/server.xml to run on a port other than the default 8082, then you must set the port in the Url to the database connector to that different port number.

This will not work: http://localhost:8082/database/myStore/allOrders. Change 8082 to your tomcat port.

Your browser is not on the same machine as the database connector

If your web browser is not running on the machine where your database connector is installed then you cannot use "localhost" in the Url. You must replace this with the name or ipaddr of the machine running the database connector.

This will not work: http://localhost:8082/database/myStore/allOrders. Change "localhost" to the actual hostname or ipaddr. 

The confguration.xml file is not found.

If the Database Connector cannot find the configuration.xml file, an error message will be reported in the browser:

Check the reported path. Verify that the configuration.xml is present in the same directory as the database.war file or in the C:\database\database-connector-2.5.0\config directory for a Standalone installation. If you are running the connector in the tomcat bundle, verify that the value of the  "frevvo.connectors.database.configuration parameter in the <frevvo-home>\tomcat\conf\dbconnector.properties file reflects the correct location of the configuration.xml.

<Parameter name="frevvo.connectors.database.configuration" value="c:\<frevvo-home>\frevvo\dbconfig\configuration.xml" override="false"/>

The format of your test query URL is invalid.

If you type an invalid URL into the browser when testing a query, you will see this message:

Revise the URL to follow the correct format.