Kbase 20811: What Are the Differences Between SQL89 ESQL/C Small and Large Clients?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
12/10/2004 |
|
Status: Unverified
GOAL:
What are the differences between SQL89 ESQL/C small and large clients?
FIX:
The fundamental difference between small and large clients is that with the large client, all the SQL processing occurs in the client, and it accesses the database in the same way a 4GL network client does. In small client applications, all the SQL processing occurs in the OID, and the client sends SQL requests to it.
A separation of an ESQL large client application into separate small client and OID processes provides the following advantages:
- Application isolation.
The OID effectively isolates all Progress database client
code, including signals and global references, from the
ESQL application environment. This enables the ability to:
- Use signals as the application requires.
- Open a global name space, thereby reducing the
potential for name conflicts with the application
code.
- Significantly reduce the size of the application
that is attributable to Progress-specific code.
- Client maintainability.
An ESQL small client is much smaller and easier to maintain,
especially on smaller workstations. It is possible to link only a
small Progress communications layer with the application
code.
- Client upgradeability.
In many instances, an ESQL small client application can
automatically benefit from enhancements to Progress database
client/server technology without relinking the application
code.
- Network efficiency.
In a network configuration where the database resides on a
separate machine, the Open Interface Driver (OID) can
provide more efficient operation by minimizing network
traffic.
It performs all of the SQL table manipulation and result set
processing that any Progress database client provides, and
sends only the requested data back to the remote ESQL small
client.