HP 3000 Manuals HP 3000 Manuals
Creating Databases
In TurboIMAGE/XL, you create a database using the following steps:
1. Create a schema. A common way of doing this is to enter the
schema into a text file created with an editor.
2. Run DBSCHEMA to generate a root file from the schema.
3. Run DBUTIL to create data sets based on the root file.
4. Create a DBEnvironment.
With TurboIMAGE/XL, a schema is required to define a database. The
schema contains definitions of all the data items in your database and
describes all the data sets in the database. It also specifies the
desired security for the database by defining passwords for specific
users. The schema can also be used to create the same database structure
in different groups and accounts or on different systems.
To access a TurboIMAGE/XL database with IMAGE/SQL, you need a
DBEnvironment. You create a DBEnvironment with a SQL START DBE NEW
statement. The statement can be issued interactively (through ISQL) or
through an application program. The START DBE NEW statement is as
follows:
START DBE 'DBEnvironmentName' NEW
The START DBE NEW statement creates a file known as a DBECon file, which
is similar to the root file in TurboIMAGE/XL. The DBECon file contains
information about startup parameters for the DBEnvironment and its logs.
START DBE NEW also creates a structure within the DBEnvironment known as
a system catalog, which is a set of information about all the databases
in the DBEnvironment.
If you use the START DBE statement and the DBEnvironment does not exist,
the system will ask if you want one automatically created. See Chapter
5, "IMAGE/SQL Tasks," for more details and an example.
After the database and DBEnvironment have been created, you must attach
the TurboIMAGE/XL database to the DBEnvironment.
Root File versus DBECon File and System Catalog
With TurboIMAGE/XL, the root file, which is generated by DBSCHEMA from
the schema, contains security information and definitions of all the data
sets in the database. The user executing DBSCHEMA becomes the database
creator.
The DBECon file in ALLBASE/SQL is created when you issue the START DBE
NEW statement in ISQL. The DBECon file, which has the same name as the
DBEnvironment, contains the name of the DBECreator and the names of the
logs associated with the DBEnvironment. The DBECon file also contains
startup parameters, such as SINGLE or MULTI user mode, but does not
contain the names of tables or other database objects; these are stored
in the system catalog.
The system catalog contains structural information about database objects
and tables, much the way the root file does for standard TurboIMAGE/XL.
This catalog serves as an internal schema for accessing data.
When a TurboIMAGE/XL database is attached to a DBEnvironment, data set
and item definitions are copied into the system catalog. This provides a
mapping to the TurboIMAGE/XL data from the DBEnvironment. The data is
not copied; it remains in the TurboIMAGE/XL database.
Naming Conventions
TurboIMAGE/XL data sets and items may contain some characters that are
not allowed in IMAGE/SQL. For example, the hyphen is not allowed in
IMAGE/SQL names. Therefore, hyphens must be represented in another way
in IMAGE/SQL, such as with an underscore (_). Specifically, the
characters not allowed in IMAGE/SQL names are: + - * / ? ' % &. For
more details, refer to the HP IMAGE/SQL Administration Guide.