SBCA ORACLE 2.6 UNIT-1 1. ANSWER ORACLE is a fourth generation relational database management system, In general, a database management system (DBMS) must be able to reliably manage a large amount of data in a multiuser environment so that many users can concurrently access the same data. All this must be accomplished while delivering high performance to the users of the database. A DBMS must also be secure from unauthorized access and provide efficient solutions for failure recovery. The ORACLE Server provides efficient and effective solutions for the major database features. ORACLE consists of many tools that allow you to create an application with ease and flexibility. You must delermine how to implement your requirements using the features available in ORACLE, along with its tools. The features and tools that you choose to use to implement your application can significantly affect the performance of your application. Several of the more useful features available to ORACLE application. developers are integrity constraints, stored procedures and packages, database triggers, cost-based optimizer, shared SQL, locking and sequences. This documentation will lead you through the main features and tools of ORACLE. It is intended to give youa partial view of what is available to you to use within the assignments. This documentation will cover ORACLE Architecture- provides a basic understanding of the "Big Picture" including the concepts and terminology of the ORACLE Server. Starting ORACLE And Other lImportant Information provides the knowledge of how to set up your account and other system environment variables. t will also provide information about how ORACLE is currently setup, which you will require, and the steps you must take to report any problems SOL'Pus (Terminal Moniton)- provides a summary of the commands that you willrequire in order to create tables and manipulate the database SQL-Loader- provides a summary of the commands that you will require to allow you to load data from a file to the database. SQL Commands -provides the syntax of some of the SaL Commands in ORACLE to help you get started. This section will only shed light on the Data Definition Language commands and wi not contain any information on querying the database (which should be covered in class). ANSWER Features of Oracle 2. lf you are using Borland's Delphi or C-Builder to develop Oracle applications, then the Direct Oracle Access component sel can help you to make a seamless integration between this great development tool and database system. Not only will your application take maximum advantage of both products, your application development process willalso benefit from the following key features: High performance Both online transaction and batch processing applications can benefit from Oracle's performance features. Direct Oracle Access, as the name suggests, directly accesses the Oracle Interface. This guarantees optimal performance for standard database access functions. Support for Array Felching, Array DML, PLUSQL Blocks, PLUSQL Tables, Local Slalement Caching and the Direct Path Load Engine enable you to optimize your application's performance crical functions even more. High performance Easy application distribution A 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. ** Application distribution Oracle Package support Most PLUSQL 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. Furthermore 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. L The Package Wizard PRESIDENCY COLLEGE 1 2.6 ORACLE SBCA The dataset component in Direct Oracle Access supports Oracle record locking, record refreshing, server generaled values, automatic sequence value generation, and BLOB compression. Master/detail relations can automalically be selup t 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). The TOracleDataSel can use much of the information in the Oracle Dictionary at run time. Server Constrainls 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 recompiling9it TOracleDataSet The TOracleData Set Query By Example mode The 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 mihimal. The user can supply simple query values such as JONES or 100, can include wildcard characlers for string values SUch as JON%, and can include comparison operators such as>, , NOT, BETWEEN, IN and so on. Query By Example Oracle Monitor To 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. The Oracle Montor Alert and Pipe events The 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. ***** ** *** * ***** **** Alert and Pipe events sQL scripts If 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. ***** SQL Scripts Advanced Queueing To take advantage of the Advanced Queuing option of Oracle8 you can make use of the TOracleQueue component. The TOracleQueue component encapsulates the bas 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 th main thread of your application. functionality of the DBMS_AQ package. It provides a convenient way to enqueue messages into a queue or to dequeue messages Session Pooling In server applications that frequently need to create sessions to process requests from client applications, it may be useful to use connection pooling. Without a poling concept, each request could lead to an actual dalabase logon and logoff. By using 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. TOracleSessionPool cormponent, you can maintain a pooB of Support for Oracle specific features Direct 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 2 PRESIDENCY COLLEGE ORACLE 2.6 SBCA for MTS 3. ANSWER SQL Commands Overview Oracle Lite uses several different types of SQL commands. This section discusses the diferent types of SQL commands. Data Definition Language (DDL) Commands Data definition language (DDL) commands enable you to perform the following tasks: Create, alter, and drop schema objects Grant and revoke privileges and roles Add comments to the data dictionary The CREATE, ALTER, and DROP commands require exclusive access to the object being acted upon. For example, an ALTER TABLE command fails if another user has an open transaction on the specified table. Data Manipulation Language (DML) Commands Data manipulation language (DML) commands query and manipulate data in existing schema objects. These.commands do not implicitly commit the current transaction. Transaction Control Commands Transaction control commands manage changes made by DML commands. Clauses Clauses are subsets of commands that modify the command. Pseudocolumns Pseudocolumns are values generated from commands that behave like columns of a table, but are not actually stored in the table. Pseudocolumns are supported by Oracle but are not part of SQL-92. 4 ANSWER Data Definition Language (DDL) Statements Data definition language (DDL) statements let you to perform these tasks: Create, alter, and drop schema objects Analyze information on a table, index, or cluster Establish auditing options Add comments to the data dictionary The CREATE, ALTER, and DROP commands require exclusive access to the specified object. For example, an ALTER TABLE statement fails if another user has an open transaction on the specified table. Oracle Database implicity commits the current transaction before and after every DDL statement. Many DDL statements may cause Oracle Database to recompile or reauthorize schema objects. For information on how Oracle Database recompiles and reauthorizes schema objects and the circumstances under which a DDL statement would cause this, see Oracle Database Concepts. DDL statements are supported by PL/SQL with the use of the DBMS_SQL package. 5. ANSWER Relational Database Management System - RDBMS A RDBMS is a term used to describe an entire suite of programs for both managing a relational database and communicating with that relational database engine. Sometimes Software Development Kit (SDK) front-end tools and complete management kits are included with relational database packages (eg: MS Access)}In other words, an RDBMS is both the database engine and any other tool that comes with in. Rebiona Databses Arelaicnaldatabase sagariedasaseldttiesdidaaandamahemaicallang.age( relaionalagebra - is aaabe bmanipuale hetaties The presertaicnddaantefamdtbesiskrowna areton Arekaicnismaeupdanumberd pes (ows) ad abues (okumms) Domains aeragedvalESwhichcanappea neah column are taken from the daman a tatatte Sae Tre AGEMbenteap t6b,otednand te AGE ateibeaniesnteag 16b5 Advantages of RDBMS Supports for very large databases. Automatic optimization of searching. 1. 2. PRESIDENCY COLLEGE ORACLE RDBMS have a simple view of the database that confirms to much of the data used in business. Structured Query Language (SQL). SBCA 3 4 5. ANSWER Ans. Data retrieval | SQL Lanquage Reference | DDL-Data Definition Language DML Data Manipulation Lanquage SIUD SELECT INSERT UPDATE DELETE 3 2. MERGE DML Data Manipulation Language S the adbreviation for Data Manipulation Language. DML is a collection of SQL commands that can be used to manipulate a data0ases oata. o language commands, which execute gueries with database objects and changes to their contents. The various DML COmnandS Can De e t reale, edit, evaluate and delete data in a database. DML commands are a subarea of SQL; the range of the SQL language is composeuO DML dnd DDL together. SIUD SIUD is the abbreviation for SELECT, INSERT, UPATE, DELETE, which are the four DML commands used for data manp ulduon See also Create SIUD Procedures INSERTEX SELECT Pleaserefer to SQL Lanquage Reference / Data Retrieval /SELECT for details. INSERT Adds one or more new rows to a specifed table. Available in gpre, DSQL, and isq Syntax INSERT (TRANSACTION transaction] INTO object [(col [. col..])] (VALUES (val [, val..]) | select_expr)}

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