METHODOLOGY:


FEATURES OF AutoCADR14 SQL EXTENSION (ASE) WITH FUNCTIONAL OVERVIEW

Introduction to The AutoCADR14 SQL Extension (ASE):

The AutoCADR14 is provided with SQL features  called AutoCAD STRUCTURED QUERY LANGUAGE ( ASE). AutoCADR14 SQL Extension (ASE) facilitates to access and manipulate non-graphic data stored in external databases. ASE provides with direct access from within AutoCADR14 to external database management system (DBMS) such as dBASE, INFORMIX, ORACLE etc. ASE provides the same command regardless of the database in use. ASE application is used to manipulate data for bills of materials( database ), asset management, estimating, or to directly access a standard parts database. It helps to establish connections between objects in the drawing and data in the database. The ASE facilitates to manipulates external data and links it to AutoCADR14 graphic entity.

 

FEATURES OF AutoCADR14 SQL Extension (SQL):

ASE provides three features that enables AutoCAD to access data in external databases: a command set, database drivers, and a programming interface. Linking graphic entities in the drawings to the external non-graphic data provides the following:

ASE FUNCTIONAL OVERVIEW:

ASE commands provides to attach, or link, graphic entities in an AutoCADR14 drawing to a row or rows in an external database. The resulting non-graphic data is available to the DBMS even when the drawing is not loaded in the AutoCADR14; the data is stored in the native external database format. The database links are stored in the AutoCADR14 drawings. Links can be modified only when the drawing containing them is loaded into AutoCADR14. The database values can, however, be changed either from within AutoCADR14 or from within AutoCADR14 or from within the DBMS. Both AutoCADR14 and the DBMS access the same data; changes made by either are reflected whether viewing the data using or using the DBMS directly.

The relationship between AutoCADR14 entities and external databases is a many-to-many relationship. AutoCADR14 entity can be attached to none,  one, or many rows. Fig. shown below gives the relationship between ASE and DBMS drivers.


 

LINKING DBASE FOR WINDOWS WITH AutoCADR14 :

There are two types of databases drivers supplied with AutoCADR14: drivers used to directly connect to specific database applications, such as Oracle and dBASE; and ODBC drivers used to connect to any database application that has a corresponding ODBC interface (Open Database Connectivity).ASE provides a set of database drivers, each of which lets us to connect to an external database. The AutoCAD SQL interface,  ASI, lets to create AutoCAD-specification applications that can access external databases.

 

Requirements for AutoCADR14 ASE and dBASE for windows are as follows:

Defining Keys:

When an entity is linked with data in an external database, specification of the row or rows in the database table is needed via a key. A key, in turn, specifies a column or set of columns in the table against which the column values are matched. For example, if the key column is AutoCADR14 and a value of 1901.0009 is specified, the PART_NO column of the table must have a value of 1901.0009 to match. A unique key matches only with one row in a table.
Same thing in our has been done to match an entity linked with data in external database. Specification of row or rows is already shown in the fig. of dBASE environment. What we select the PART_NO column as the characteristic to match with the unique row shown in the database table. PART_NO is already specified for the standard drawing.
 

Interface from AutoCAD to DBMS

From DOS operating system, we can open our database file in C:/WINNT/DBASE/ directory by simply typing dbase and after then typing command assist.  By this procedure, we enter into dBASE environment having the file REAR_AXL.dbf file containing data of our associated standard drawing to be opened in AutoCADR14 environment. WE can update our database even in dBASE environment which will also be reflected in AutoCADR14 whatever the changes be made. In the dBASE III PLUS DBMS, sub directories represent the logical database and dBASE III PLUS .dbf represent the tables. For all this an environment is set named WINNT/DBASE. The figure shown above gives details about our database design for a specific drawing with different attributes. The same structure of our database is used to show in AutoCADR14 environment.

Loading the On-Screen AEC menu

Program for generating a menubar with the name,"Mymenu" is written to run in the environment of AutoCADR14. This menubar displays the drawing files and menu files organized in an hierarchical manner. The "Mymenu"  is selected from the shown Menufiles and then click open button. Then Mymenu menubar gets opened in the environment of AutoCADR14. If we want to get back to "ACAD" menu then we have to type menu in command prompt and then do the same step detailed above for "Mymenu" menubar. The figure below show the menufile and the buttons in AutoCADR14 environment.



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