 |
» |
|
|
|
A TurboIMAGE/XL schema is made up of three parts:
The Password Part was discussed in the previous section.
The Item Part contains the list of attributes, called items, in the
database. Only a single definition is required, even if the item
is used in the database in more than one set. Also included in the Item
Part is each item's data type and length. Data types are discussed in
the section, "Mapping of Data Types," in
Chapter 3 and will not be addressed here.
The Set Part describes the entities, the set type, the security, and the
items that make up the entry. Size is also defined, with a capacity
value that indicates the maximum number of entries for that entity.
The database schema presented in this section is included with the
IMAGE/SQL product and is found in SAMPLEDB.SYS. Practice with this
database is in Chapter 6, "Practicing with IMAGE/SQL Using MusicDBE."
The schema for the sample database is as follows:
Begin data base Music;
Passwords: 10 MGR;
20 DIR;
30 ANNCR;
Items:
AlbumCode, I2;
AlbumCost, P8;
AlbumTitle, X40;
Announcer, X40;
Birth, X16;
BirthPlace, X40;
Comment, X80;
ComposerName, X16;
DateRecorded, X16;
Death, X16;
EndTime, X16;
Medium, X2;
MfgCode, X40;
Performers, X40;
RecordingCo, X10;
SelectionName, X40;
StartTime, X16;
Timing, X16;
Sets:
Name: Albums, Manual(10,20,30/10,20);
Entry: AlbumCode (2),
AlbumTitle,
Medium,
AlbumCost,
RecordingCo,
DateRecorded,
MfgCode,
Comment;
Capacity: 1000;
Name: Composers, Manual (10,20,30/10,20);
Entry: ComposerName (1),
Birth,
Death,
Birthplace,
Comment;
Capacity: 1000;
Name: Selections-A, Automatic;
Entry: SelectionName(2);
Capacity: 1000;
Name: Selections, Detail (10,20,30/10,20);
Entry: AlbumCode (Albums),
SelectionName (Selections-A),
ComposerName (Composers),
Timing,
Performers,
Comment;
Capacity: 1000;
Name: Log, Detail (10,20,30/10,30);
Entry: AlbumCode (Albums),
SelectionName (Selections-A),
StartTime,
EndTime,
Announcer;
Capacity: 1000;
End.
|
The next step is to create a root file for this database with DBSCHEMA
as follows:
:FILE DBSTEXT = MUSICSCH.SAMPLEDB.SYS
:RUN DBSCHEMA.PUB.SYS;PARM=3
|
The schema is displayed here, followed by this detail:
DATA SET TYPE FLD PT ENTR MED CAPACITY BLK BLK DISC
NAME CNT CT LGTH REC FAC LGTH SPACE
ALBUMS M 8 2 98 115 1000 4 461 1008
COMPOSERS M 5 1 84 95 1000 4 381 752
SELECTIONS-A A 1 2 20 37 1000 10 371 304
SELECTIONS D 6 3 98 110 1000 4 441 1008
LOG D 5 2 58 66 1001 7 463 576
TOTAL DISC SECTORS INCLUDING ROOT: 3664
NUMBER OF ERROR MESSAGES: 0
ITEM NAME COUNT: 18 DATA SET COUNT: 5
ROOT LENGTH: 916 BUFFER LENGTH: 463 TRAILER LENGTH: 256
ROOT FILE MUSIC CREATED.
|
|
