Easy application distribution
Direct Oracle Access application does not require middleware like the
BDE or ODBC, it merely requires Oracle SQL*Net or Net8. Consequently you
can deploy your application without many of the version dependency or
configuration problems typically involved with middleware installation.
Oracle Package support
PL/SQL code in Oracle databases is programmed in packages. Direct
Oracle Access provides a TOraclePackage component that allows you to
easily call packaged program units without detailed declarations of
these program units and their parameters.
Direct Oracle Access includes a Package Wizard that can generate classes
to encapsulate the program units and record types defined in packages.
This will make your Oracle packages a natural extension of the Object
Pascal or C++ language.
dataset component in Direct Oracle Access supports Oracle record
locking, record refreshing, server generated values, automatic sequence
value generation, and BLOB compression. Master/detail relations can
automatically be setup if a foreign key exists between the master and
detail table or if the master table contains one or more collection
columns or attributes (nested table or varray).
TOracleDataSet can use much of the information in the Oracle Dictionary
at run time. Server Constraints can be checked on the client, and
constraint error messages can be read from a message table. Format
masks, range values and default values can also be read from the
dictionary. This allows you to create applications with a minimum amount
of 'database knowlegde' compiled into the executable, dynamically
adopting changes in the database without even recompiling it.
Query By Example mode
TOracleDataSet component has a Query By Example mode that enables you
to provide QBE Forms in your application without any additional
programming, and without any additional components or controls. The
resulting QBE queries are performed on the Oracle Server, so that
performance will be optimal and network traffic will be minimal. The
user can supply simple query values such as JONES or 100, can include
wildcard characters for string values such as JON%, and can include
comparison operators such as >, <, NOT,BETWEEN, IN and so on.
monitor the database access activities of your Direct Oracle Access
application you can use the Oracle Monitor utility. It displays the SQL,
variables, timestamp, elapsed time, network statistics, database
statistics and query execution plan of each activity. This can be
helpful to find performance bottlenecks, for tuning purposes, and to
solve application errors.
Alert and Pipe events
Oracle Server includes a dbms_alert and dbms_pipe package for event
processing. The TOracleEvent in Direct Oracle Access can function as a
receiver for these events. It works in a background thread of your
application, and can propagate database events to the familiar object
events. These events can occur synchronously or asynchronously with the
main thread of your application.
you need to execute many data definition language (DDL) statements, for
example to perform the database installation part of your application,
you can use the TOracleScript component. It has a property editor that
allows you to develop the script and the individual commands. The
extendible script language follows the basic SQL*Plus syntax and
supports all SQL statements. It also supports substitution variables to
make your scriptscustomizable.
take advantage of the Advanced Queuing option of Oracle8 you can make
use of the TOracleQueue component. The TOracleQueue component
encapsulates the basic functionality of the DBMS_AQ package. It provides
a convenient way to enqueue messages into a queue or to dequeue
messages from a queue. Messages can be dequeued in a background thread
of your application, and the events that are generated in threaded mode
can occur synchronously or asynchronously with the main thread of your
applications that frequently need to create sessions to process requests
from client applications, it may be useful to use connection pooling.
Without a pooling concept, each request could lead to an actual database
logon and logoff. By using the TOracleSessionPool component, you can
maintain a pool of database sessions that can be used and reused for
different requests. You can define the minimum an maximum number of
sessions in the pool, define the TimeOut behavior for idle sessions in
the pool, and preset the username, password and database.
Support for Oracle specific features
Oracle Access supports many Oracle specific features. Besides the
features mentioned above, it supports Oracle8 and Oracle8i features like
LOB Locators, Objects & References, XMLTYPE, Timestamps, Scrollable
Queries, Password Expiration, External Procedure development, and the
Oracle Services for MTS.