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Generating the Mimer SQL System Databanks


The Mimer SQL system databanks SYSDB, TRANSDB, LOGDB and SQLDB are generated by the SDBGEN program.

SDBGEN will load the system tables, see Data Dictionary Tables, and defines the data dictionary views detailed in the Mimer SQL Reference Manual.

Note: A databank created for one SYSDB cannot be accessed by using a different SYSDB even if identical data dictionary definitions are created in it.

Setting the Initial Size

The initial size for each of the Mimer SQL system databanks can be specified.

The size for the databanks is specified in Mimer SQL pages. The size of a Mimer SQL page is 2 kilobytes.

Creating SYSADM

The database administration ident SYSADM is also created and a password (passwords are case-sensitive) must be specified for this ident.

For security reasons, the password specified for SYSADM is not echoed on the screen when it is entered. It should be chosen carefully and changed at appropriate intervals using Mimer SQL with the ALTER IDENT statement.

Caution: Care should be taken to safeguard the SYSADM password, because if it is lost it cannot be retrieved from the system and it is not possible to set a new one.

UNIX: A local database is set up on a UNIX node by running the dbinstall command (see the dbinstall man-page) and SDBGEN is started automatically when required.
The databank files are by default created in the database home directory which is not the ideal arrangement from a security and performance point of view, see Re-creating TRANSDB, LOGDB and SQLDB for guidelines relating to placement and organization.
If there is more than one disk available on the system, it is recommended that directories be created on those disks specifically for locating databanks. When created, the LOCAL definition for the database should be updated in the /etc/sqlhosts file by changing the single home directory path to a directory path list that includes these directories. The list is colon separated as can be seen in the following example:
hotel /usr/db/hotel:/extra/db/hotel:/extra2/db/hotel
After this update is made, the database server can be stopped and the selected databank files can be moved from the database home directory to their new locations. When moved, the database server can be started again.

VMS: In order to create the Mimer SQL system databanks for a local database on a VMS node, an entry for the database must be specified in the SQLHOSTS file. SDBGEN should then be executed to create the actual database. See SDBGEN Syntax for information on how to run SDBGEN.

Win: You set up a local database on a Windows node by running the Mimer Administrator. The Mimer Administrator invokes the SDBGEN program in order to create the system databanks when required.
The system databanks are distributed automatically, depending on the number of disks available. On-line Windows help is provided with both the Mimer Administrator and SDBGEN to guide you through setting up a local database.

SDBGEN Syntax

UNIX: On UNIX, the dbinstall utility is used to create the system databanks.

Win: On Windows, the Mimer Administrator is used to create the system databanks.

The SDBGEN command has two purposes. Either to create a new set of system databank files, or to upgrade database files created in an earlier version of Mimer SQL to version 8.2. (Upgrade can be done for databank files created by Mimer SQL version 7.1 and later.)

The SDBGEN program is controlled by flagged information specified on the command-line.

The syntax (expressed in VMS-style) for creating databank files is as follows:

 SDBGEN [/PASSWORD=passw] [dbase] [syssz] [tfn] [tsz] [lfn] [lsz] [sfn] [ssz]

sdbgen Command-line Arguments

When creating databanks files:

UNIX-style
VMS-style
Function
 -p password
 /PASSWORD=password
Password for SYSADM
 dbase
 dbase
Database name
 syssz
 syssz
Size of SYSDB
 tfn
 tfn
Filename for TRANSDB
 tsz
 tsz
Size of TRANSDB
 lfn
 lfn
Filename for LOGDB
 lsz
 lsz
Size of LOGDB
 sfn
 sfn
Filename for SQLDB
 ssz
 ssz
Size of SQLDB

If the password parameter is omitted, the SDBGEN command will prompt for all parameters that are missing, including the password for the SYSADM user.

If the password parameter is given, the SDBGEN command will not prompt for any missing parameters, but use default values.

If the dbase parameter is missing, the environment variable MIMER_DATABASE is used to determine which database the databank files should be created for.

The SDBGEN program syntax (expressed in VMS-style) for upgrading databank files to Mimer SQL version 8.2 is as follows:

 SDBGEN /UPGRADE [dbase]

sdbgen Command-line Arguments - Upgrading

When upgrading databanks:

UNIX-style
VMS-style
Function
 -u
 /UPGRADE
Upgrade existing database to Mimer SQL version 8.2
 dbase
 dbase
Database name

UNIX: The UNIX-style command-line flags must be used on a UNIX machine.

VMS: Either the UNIX-style or the VMS-style command-line flags may be used on a VMS machine - see the Mimer SQL VMS Guide for more details.

Establishing the Ident and Data Structure

Once the local database environment has been created for a Mimer SQL database (database name, server parameters, system databanks, the SYSADM ident plus the system tables and views), the data structure for the database (idents, user databanks, tables, and so on) can be created using Mimer SQL data definition statements.

BSQL allows the execution of a sequential file which can then be used as a permanent record of the CREATE statements used to create the database objects, see the Mimer SQL User's Manual.

BSQL also supports the saving of input and/or output to a log file (using the LOG command), so this facility could be used to create a permanent record of an interactive BSQL session which could be run again at a later date. BSQL, however, only has limited support for error handling.

An application program using embedded SQL, JDBC or ODBC can also be used, but this requires more work on the part of the programmer and it provides a less concise record of the ident and data structure in the database.

Third party SQL tools are also available which may be used to create the database data structure.

Note: A sequential file intended for non-interactive execution through the BSQL facility may include username and password information relating to any CONNECT statements used. For security reasons, such a file should be well protected in the operating system, preferably with any username and password edited out of any permanent copy of the file.


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