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A Simple Data Modeling Tool with entities, relations, attributes, Classes/Objects

greghop

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24 Nov 2002

This database tool supports simple data modeling with entities, relations, attributes, classes & objects. Classes are like type definitions. Objects are like instances of the classes.

Download source code - 41 Kb

Sample Image

Introduction

This source code is a small prototype tool for data modeling that supports entities, relations and attributes. More features are described in the Help File Contents below. Commercial data modeling tools like Erwin & SA are used to design, modify & maintain databases.

Some crunchy technical tidbits from the source files:

HTML include multiple JScript source files - file dbtv3.hta, lines 7-18
HTML HTA tag for local applications - file dbtv3.hta, lines 9
Connect HTML initialize & terminate to JScript function - file dbtv3.hta.js, lines 19
Connect HTML buttons to JScript functions - file dbtv3.hta, lines 22-33
Connect HTML listboxes to JScript functions - file dbtv3.hta, lines 34-37
HTML read single line string - file dbtv3.hta, lines 38-45
HTML read multiline listbox - file dbtv3.hta, lines 46-52
HTML STYLE absolute positioning for widgets - file dbtv3.hta, lines 22-55
ADO Connect strings for Jet 4.0 and SQL Server 2000 - file global3.js, lines 7-8
Create new XML object - file global3.js, lines 93
Read XML text file into memory - file global3.js, lines 94-102
Open new text file for disk output - file global3.js, lines 155-156
Write line to disk file - file global3.js, lines 192
Open new HTML window for output - file global3.js, lines 145-147
Write line to HTML window - file global3.js, lines 185
Clear HTML listbox - file screen3.js, lines 12,65
Get selected index from HTML listbox - file screen3.js, lines 21,74
Get selected item from HTML listbox - file screen3.js, lines 43-48,74-80
Add item to HTML listbox - file screen3.js, lines 56-57,109-110
Nested function calls - file screen3.js, lines 27,80
Hide HTML widgets - file screen3.js, lines 192-195,360-361
Show HTML widgets - file screen3.js, lines 294-295,417
Set cursor focus on HTML widget - file screen3.js, lines 296
Call JScript function using a variable - file screen3.js, lines 266-270,473-476
ADO compact Jet MDB file - file adodb3.js, lines 40-41
ADO create new Jet MDB file - file adodb3.js, lines 110-112
ADO connect to database - file adodb3.js, lines 69-70
ADO disconnect from database - file adodb3.js, lines 86-91
ADO create new SQL tables - file adodb3.js, lines 159-184,200-239
ADO create new SQL table columns - file adodb3.js, lines 159-184,200-239
ADO create new SQL table autoincrements - file adodb3.js, lines 159-184,200-239
ADO create new SQL table indexes - file adodb3.js, lines 159-184,200-239
ADO run SQL and return recordset - file adodb3.js, lines 565,610-637
ADO run SQL and don't return recordset - file adodb3.js, lines 516-534
ADO get table, column & index database info - file adodb3.js, lines 729-731,754-782
Use try/catch for error handling - file adodb3.js, lines 67-77,84-98
Run DOS command from JScript - file adodb3.js, lines 42-48
Parse file path - file adodb3.js, lines 26-36
ADO add new record to table - file ents3.js, lines 26-35,509-518
ADO get @@IDENTITY from newly added record - file ents3.js, lines 37,520
XML nested function calls - file ents3.js, lines 138,144,148
XML to get node list - file ents3.js, lines 138
XML to get node text value - file ents3.js, lines 148
ADO loop over recordset - file ents3.js, lines 313-322,356-364
SQL to delete a record - file ents3.js, lines 67
SQL to update a record - file ents3.js, lines 105
SQL to read a record - file ents3.js, lines 216
SQL query with triple joins - file ents3.js, lines 691-697

Help File Contents

Concepts
Screen Layout
Quick Demo Tour
Button Details
Constraints
Test Data
SQL Tables
ZIP Files

1. Concepts

The database tool supports simple data modeling with entities, relations, attributes, classes & objects. Classes are like type definitions. Objects are like instances of the classes.

Some websites with much more info about data modeling

2. Screen Layout

+----------------------------------------+
| Database Tool                          |
| H  +--------+  +--------+  +--------+  |
| C  |        |  |        |  |        |  |
| T  |  ENTS  |  |  RELS  |  | ATTRS  |  |
| I  |        |  |        |  |        |  |
| E  |        |  |        |  |        |  |
| M  +--------+  +--------+  +--------+  |
|                                        |
| C  +--------------------+  +--------+  |
| O  |                    |  |        |  |
| C  |  OUTPUT            |  | MULTI  |  |
| D  |                    |  |        |  |
| U  |                    |  |        |  |
| Q  +--------------------+  +--------+  |
|    |  QUERY             |    O  C      |
|    +--------------------+              |
|                                        |
+----------------------------------------+

Buttons are aligned down the left edge of screen

HELP	Show help info
CONFIG	Configure database
TEST	Write test data
IMPORT	Import XML data
EXPORT	Export XML data
MISC	Turn trace on/off
CLASSES	Switch to class data
OBJECTS	Switch to object data
CREATE	Create data
DELETE	Delete data
UPDATE	Update data
QUERIES	Run SQL statements

Screen areas are named as follows. Clicking on data in the ENTS, RELS & ATTRS areas will then show detail information about the data in the OUTPUT area.

ENTS	Shows entity data
RELS	Shows relation data
ATTRS	Shows attribute data
OUTPUT	Shows output data from pressing buttons
QUERY	Appears when using buttons
MULTI	Multiple usage area for buttons
OK	Appears when using buttons
CANCEL	Appears when using buttons

3. Quick Demo Tour

Follow these steps

Start database tool (dbtv3.hta)
Click CONFIG button
Select option "JET4.0"
Enter MDB file name
Select option "create new MDB & new tables"
Click OK button

A newly created MDB file should have been written to disk. See the OUTPUT screen area for more detailed information.

Click TEST button
Select option "employees projects resources"
Click OK button

The sample test data should have been written to disk. See the OUTPUT screen area for more detailed information.

Click CLASSES button
Click OBJECTS button
Click records in ENTS, RELS, ATTRS screen areas

The screen areas are refreshed when switching between the classes & objects. Clicking on a record will refresh OUTPUT screen area with detailed info about the record.

4. Button Details

HELP Button

Show this help file
CONFIG Button

   Configure database for Jet40 or SQL Server 2000

   Jet40
   Create new MDB & new tables
   Existing MDB & existing tables
   Existing MDB & create new tables
   Existing MDB & compact MDB

   SQL Server 2000
   Create new tables
   Use existing tables
   Truncate existing tables
TEST Button

   Write test data to tables

   Employees resources projects
   Alphanumeric random
IMPORT Button

Import XML data from flat file
EXPORT Button

Export XML data to flat file
MISC Button

Turn trace window on/off
CLASSES Button

Switch to class data
OBJECTS Button

Switch to object data
CREATE Button

   Create Class Entity
   Create Class Relation
   Create Class Attrib
   Create Object Entity
   Create Object Relation
   Create Object Attrib
DELETE Button

   Delete Class Entity
   Delete Class Relation
   Delete Class Attrib
   Delete Object Entity
   Delete Object Relation
   Delete Object Attrib
UPDATE Button

   Add Attrib to Class Entity
   Add Attrib to Class Relation
   Add Attrib to Object Entity
   Add Attrib to Object Relation
   Remove Attrib from Class Entity
   Remove Attrib from Class Relation
   Remove Attrib from Object Entity
   Remove Attrib from Object Relation
   Change Class Entity name
   Change Class Relation name
   Change Class Attrib name
   Change Object Attrib value
QUERIES Button

Run SQL statements

5. Constraints

The database tool implements a few useful constraints.

Names must be unique for entities, relations & attributes.
Relations have a source & destination, either of which can be an entity or another relation.
Attributes can be added to both entities & relations.
Object attributes can only be added to the object entities & relations if the class entity/relation already has the class attribute.
Source & destination objects for object relations must be same class as the source & destination of the class relation.
Deleting class entities, relations & attributes also automatically deletes any objects created for these classes.
Deleting entities or relations also automatically deletes their used attributes, but not the attribute itself.
Deleting class/object entities/relations will leave dangling source & destination pointers if they are used by relations.

6. Test Data

Use the TEST button to create sample data.

Option "alphanumeric random" generates lots of test data.

Option "employees projects resources" has 3 class entities, 2 class relations, 7 class attributes, 9 object entities, 9 object relations & 27 object attributes. The TEST1.MDB file in ZIP already has this sample data created.

Class Entities: Employees, Resources, Projects
Class Relations: AssignedTo, BudgetedFor
Class Attributes: Name, JobTitle, PayRate, Equipment,Supplies, Location, Priority

7. SQL Tables

The database tool uses these 8 SQL tables. Column headings for data are shown in the ENTS, RELS, ATTRS & OUTPUT areas.

Table:   CLSENTS                Table:   OBJENTS
Column:  ID                     Column:  ID
Column:  NAME                   Column:  CLSID

Table:   CLSRELS                Table:   OBJRELS
Column:  ID                     Column:  ID
Column:  NAME                   Column:  CLSID
Column:  SRCID                  Column:  SRCID
Column:  SRCTYP                 Column:  SRCTYP
Column:  DSTID                  Column:  DSTID
Column:  DSTTYP                 Column:  DSTTYP

Table:   CLSATTRS               Table:   OBJATTRS
Column:  ID                     Column:  ID
Column:  NAME                   Column:  CLSID
                                 Column:  ATTRVAL

Table:   CLSHASATTRS            Table:   OBJHASATTRS
Column:  ATTRID                 Column:  ATTRID
Column:  USEDBYID               Column:  USEDBYID
Column:  USEDBYTYP              Column:  USEDBYTYP

8. ZIP FILES

The DBTV3.ZIP file should contain these files

10/12/2002  12:55 AM            17,974 adodb3.js
10/12/2002  12:55 AM            19,564 attrs3.js
10/12/2002  12:55 AM            37,716 buttns3.js
10/12/2002  12:55 AM             1,926 dbic1.ico
10/12/2002  12:55 AM             1,926 dbic2.ico
10/12/2002  12:55 AM             1,926 dbic3.ico
10/12/2002  12:55 AM             1,926 dbic4.ico
10/12/2002  12:55 AM             6,483 dbtv3.hta
10/12/2002  12:55 AM            20,462 ents3.js
10/12/2002  12:55 AM             6,331 global3.js
10/12/2002  12:55 AM            19,764 gnugpl.js
10/12/2002  12:55 AM             9,803 readme3.txt
10/12/2002  12:55 AM            30,166 rels3.js
10/12/2002  12:55 AM            19,488 screen3.js
10/12/2002  12:55 AM           249,856 test1.mdb

DATABASE TOOL VERSION 3
COPYRIGHT(C) 2002 GCH Productions
GNU GENERAL PUBLIC LICENSE included by reference
WWW.GREGHOP.COM

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