Structured Query Language (SQL) - Cultural View of Technology

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PL/SQL 74 PL/SQL PL/SQL (Procedural Language/Structured Query Language) is Oracle Corporation's procedural extension language for SQL and the Oracle relational database. PL/SQL's general syntax resembles that of Ada. PL/SQL is one of three key programming languages embedded in the Oracle Database, along with SQL itself and Java. PL/SQL is available in Oracle Database (since version 7), TimesTen in-memory database (since version 11.2.1), [1] IBM DB2 (since version 9.7) [2] . Introduction PL/SQL supports variables, conditions, loops and exceptions. Arrays are also supported, though in a somewhat unusual way, involving the use of PL/SQL collections. PL/SQL collections are a slightly advanced topic. Implementations from version 8 of Oracle Database onwards have included features associated with object-orientation. PL/SQL program units (essentially code containers) can be compiled into the Oracle database. Programmers can thus embed PL/SQL units of functionality into the database directly. They also can write scripts containing PL/SQL program units that can be read into the database using the Oracle SQL*Plus tool. Once the program units have been stored into the database, they become available for execution at a later time. While programmers can readily embed Data Manipulation Language (DML) statements directly into their PL/SQL code using straight forward SQL statements, Data Definition Language (DDL) requires more complex "Dynamic SQL" statements to be written in the PL/SQL code. However, DML statements underpin the majority of PL/SQL code in typical software applications. In the case of PL/SQL dynamic SQL, early versions of the Oracle Database required the use of a complicated Oracle DBMS_SQL package library. More recent versions have however introduced a simpler "Native Dynamic SQL", along with an associated EXECUTE IMMEDIATE syntax. Oracle Corporation customarily extends package functionality with each successive release of the Oracle Database. PL/SQL program units Anonymous Blocks Anonymous blocks [3] form the basis of the simplest PL/SQL code, and have the following structure: DECLARE BEGIN EXCEPTION END label; Type / item / function / procedure declarations Statements Exception handlers The and the DECLARE and EXCEPTION sections are optional. Exceptions, errors which arise during the execution of the code, have one of two types: 1. Predefined exceptions 2. User-defined exceptions.
PL/SQL 75 User-defined exceptions are always raised explicitly by the programmers, using the RAISE or RAISE_APPLICATION_ERROR commands, in any situation where they have determined that it is impossible for normal execution to continue. RAISE command has the syntax: RAISE ; Oracle Corporation has pre-defined several exceptions like NO_DATA_FOUND, TOO_MANY_ROWS, etc. Each exception has a SQL Error Number and SQL Error Message associated with it. Programmers can access these by using the SQLCODE and SQLERRM functions. The DECLARE section defines and (optionally) initialises variables. If not initialised specifically, they default to NULL. For example: declare number1 number(2); number2 number(2) := 17; -- value default text1 varchar2(12) := 'Hello world'; text2 date := SYSDATE; -- current date and time begin end; SELECT street_number INTO number1 FROM address WHERE name = 'INU'; The symbol := functions as an assignment operator to store a value in a variable. The major datatypes in PL/SQL include NUMBER, INTEGER, CHAR, VARCHAR2, DATE, TIMESTAMP, TEXT etc. Functions Functions in PL/SQL are a collection of SQL and PL/SQL statements that perform a task and should return a value to the calling environment. User defined functions are used to supplement the many hundreds of functions built in by Oracle. There are two different types of functions in PL/SQL. The traditional function is written in the form: CREATE OR REPLACE FUNCTION [(input/output variable declarations)] RETURN return_type [AUTHID ] BEGIN [Exception END; [declaration block] RETURN ; exception block] RETURN ; Pipelined Table Functions are written in the form: CREATE OR REPLACE FUNCTION [(input/output variable declarations)] RETURN return_type [AUTHID ] []
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Structured Query Language (SQL) SQL
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Nested SQL 72 Object-oriented SQL 7
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SQL 1 SQL Paradigm Multi-paradigm A
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SQL 3 result set. SELECT * FROM Boo
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SQL 5 • MERGE is used to combine
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SQL 7 REVOKE SELECT, UPDATE ON My_t
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SQL 9 2008 SQL:2008 Legalizes ORDER
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SQL 11 [9] ANSI/ISO/IEC Internation
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SQL:2003 13 [11] http://www.iso.org
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Advantage Database Server 15 • Sm
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Call Level Interface 17 Call Level
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Check Constraint 19 Check Constrain
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Commit (data management) 21 Commit
Page 27 and 28: Correlated subquery 23 Correlated s
Page 29 and 30: CUBRID 25 Linux Foundation Silver S
Page 31 and 32: CUBRID 27 References [1] http://www
Page 33 and 34: Cursor (databases) 29 Scrollable cu
Page 35 and 36: Cursor (databases) 31 Disadvantages
Page 37 and 38: Data Definition Language 33 Data De
Page 39 and 40: Data Manipulation Language 35 Data
Page 41 and 42: Database Console Commands (Transact
Page 47 and 48: DbForge Studio for MySQL 43 • Dat
Page 49 and 50: Declarative Referential Integrity 4
Page 51 and 52: Devgems Data Modeler 47 External li
Page 53 and 54: Embedded SQL 49 External links •
Page 55 and 56: EnterpriseDB 51 EnterpriseDB also o
Page 57 and 58: Epictetus Database Client 53 Extern
Page 59 and 60: Foreign key 55 SET NULL The foreign
Page 61 and 62: FSQL 57 Comparator for Possibility
Page 63 and 64: Hint (SQL) 59 Hint (SQL) In various
Page 65 and 66: HSQLDB 61 Transaction support HSQLD
Page 67 and 68: MaxDB 63 MaxDB Stable release 7.6.0
Page 69 and 70: Meta-SQL 65 Meta-SQL 'Meta-SQL' Use
Page 71 and 72: MySQL Workbench 67 MySQL Migration
Page 73 and 74: MySQL Workbench 69 [14] MySQL Workb
Page 75 and 76: Navicat 71 Free version Navicat Lit
Page 77: PL/pgSQL 73 PL/pgSQL PL/pgSQL (Proc
Page 81 and 82: PL/SQL 77 A selection of other data
Page 83 and 84: PL/SQL 79 Array handling PL/SQL ref
Page 85 and 86: PL/SQL 81 Similar languages PL/SQL
Page 87 and 88: Query optimizer 83 Join ordering Th
Page 89 and 90: Query plan 85 Query plan A query pl
Page 91 and 92: Rollback (data management) 87 Rollb
Page 93 and 94: SQL CLR 89 External links • MSDN:
Page 95 and 96: SQL Problems Requiring Cursors 91 S
Page 97 and 98: SQL injection 93 Incorrect type han
Page 99 and 100: SQL injection 95 mysql_query($query
Page 101 and 102: SQL/CLI 97 SQL/CLI The SQL/CLI, or
Page 103 and 104: SQL/Schemata 99 SQL/Schemata The SQ
Page 105 and 106: SQLPro SQL Client 101 SQLPro SQL Cl
Page 107 and 108: Scriptella 103 Scriptella Stable re
Page 109 and 110: SQL/JRT 105 SQL/JRT The SQL/JRT, or
Page 111 and 112: SQuirreL SQL Client 107 History The
Page 113 and 114: Table (database) 109 An equally val
Page 115 and 116: Truviso 111 Truviso Industry Softwa
Page 117 and 118: User-defined function 113 User-defi
Page 119 and 120: User-defined function 115 SAS_Stude
Page 121 and 122: View (database) 117 View (database)
Page 123 and 124: View (database) 119 for processing.
Page 125 and 126: Windows Internal Database 121 Exter
Page 127 and 128: XLeratorDB 123 Analytic functions S
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XLeratorDB 125 [27] See general Bus
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Article Sources and Contributors 12
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Image Sources, Licenses and Contrib
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