DB-START


Syntax

 

DB-START {-nt}

 

The -n option specifies the database to pause (Note: This option is restricted to jBASE 5)

The -t option permits users inside a transaction to continue until it terminates the transaction by either a commit (TRANSEND) or a rollback (TRANSABORT).

 

Note: This utility is only available in jBASE 5.2 and later.

 

This command is used to start a database. Upon completion, users/applications which have been configured to use this database, may then do so. Prior to this point the following message will be displayed to the user/application :

 

jBASE: Database not started

 

The use of a particular database is trapped very early on in the creation of an application process. If the expectation is that the database should be available for use, then the system administrator should be contacted for resolution.

 

The DB-START command not only control access to a particular database, but is used also to define the location of the configuration files for Transaction Journaling operations. If the “-t” switch is not used, then the default location ($JBCRELEASEDIR or %JBCRELEASEDIR% for Windows platforms, will be used to record the location of the “config” directory/folder. This information is used by the “Warmstart” facility in order to provide recovery in case of power failure.

 

The DB-START command will write two entries into the “databases” directory/folder:

 

The first file will be named after the Database name as specified by the “-n” switch. If there is not database name specified, then this will default to the creation of a file called “default”. This file is used to hold the status of the database. This file will contain the following identifier :

 

JBC__DB

 

The remainder of the file contains information about the database itself, notably the state of the database.

 

The second file involved in recovery is the “databases_defined” file within the “databases” directory/folder. If this file does not exist, then it will be created during the execution of the DB-START command. Each entry within the “databases_defined” file will take the following form:

 

database_name $JBCRELEASEDIR/%JBCRELEASEDIR% TJ config location

 

e.g. for Unix/Linux platforms :

 

default /home/jbase /home/tjlogs

Sales /home/jbase /home/SalesLogs

Accounts /home/jbase /home/AcctsLogs

HR /home/jbase /home/tjlogs

 

And for Windows platforms:

 

Default C:\jbase4.1 C:\jbase4.1\tjlogs

Sales C:\jbase4.1 C:\SalesLogs

Accounts C:\jbase4.1 C:\AcctsLogs

HR C:\jbase4.1 C:\jbase4.1\tjlogs

 

Note: Each field is separated by a space character.

 

The above example shows a sample configuration. The databases “default” and “HR” will both use the default configuration for Transaction Journaling, whereas “Sales” and “Accounts” will each have their own set of Transaction Journal log files. All databases will use the same set of jBASE executables.


Utilities