Oracle SQL Developer

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SQL and PL/SQL Programming with UnicodeCharacter semantics is useful for defining the storage requirements for multibytestrings of varying widths. For example, in a Unicode database (AL32UTF8), supposethat you need to define a VARCHAR2 column that can store up to five Chinesecharacters together with five English characters. Using byte semantics, this columnrequires 15 bytes for the Chinese characters, which are three bytes long, and 5 bytes forthe English characters, which are one byte long, for a total of 20 bytes. Using charactersemantics, the column requires 10 characters.The expressions in the following list use byte semantics. Note the BYTE qualifier in theVARCHAR2 expression and the B suffix in the SQL function name.■VARCHAR2(20 BYTE)■ SUBSTRB(string, 1, 20)The expressions in the following list use character semantics. Note the CHAR qualifierin the VARCHAR2 expression.■VARCHAR2(20 CHAR)■ SUBSTR(string, 1, 20)This topic includes the following topic:■ NLS_LENGTH_SEMANTICS on page 11-1811.2.9.1 NLS_LENGTH_SEMANTICSThe NLS_LENGTH_SEMANTICS parameter specifies BYTE (default) or CHAR semantics.By default, the character data types CHAR and VARCHAR2 are specified in bytes, notcharacters. Hence, the specification CHAR(20) in a table definition allows 20 bytes forstoring character data.NLS_LENGTH_SEMANTICS enables you to create CHAR, VARCHAR2, and LONG columnsusing either byte or character length semantics. NCHAR, NVARCHAR2, CLOB, and NCLOBcolumns are always character-based. Existing columns are not affected.Example 11–15 shows an example of creating a table. When the database character setis WE8MSWIN1252, the last_name column of the table can hold up to 10 WesternEuropean characters, occupying a maximum of 10 bytes. When the database characterset is Unicode (AL32UTF8), last_name can still hold up to 10 Unicode charactersregardless of the language; however, it can occupy a maximum of 40 bytes.Example 11–15 Length Semantics and CREATE TABLECREATE TABLE temp_employees_table( employee_id NUMBER(4), last_name VARCHAR2(10 CHAR), job_id VARCHAR2(9),manager_id NUMBER(4), hire_date DATE, salary NUMBER(7,2),department_id NUMBER(2)) ;See Also:■Oracle Database Concepts for more information about lengthsemantics11.3 SQL and PL/SQL Programming with UnicodeSQL is the fundamental language with which all programs and users access data in anOracle database either directly or indirectly. PL/SQL is a procedural language thatcombines the data manipulating power of SQL with the data processing power of11-18 SQL Developer Online Help
SQL and PL/SQL Programming with Unicodeprocedural languages. Both SQL and PL/SQL can be embedded in other programminglanguages.Oracle Express provides products such as SQL and PL/SQL for inserting andretrieving Unicode data. Data is transparently converted between the database andclient programs, which ensures that client programs are independent of the databasecharacter set and national character set. In addition, client programs are sometimeseven independent of the character data type, such as NCHAR or CHAR, used in thedatabase.The PL/SQL and SQL engines process PL/SQL programs and SQL statements onbehalf of client-side programs such as server-side PL/SQL stored procedures. Theyallow PL/SQL programs to declare CHAR, VARCHAR2, NCHAR, and NVARCHAR2variables and to access SQL CHAR and NCHAR data types in the database.This topic describes Unicode-related features in SQL and PL/SQL that you can deployfor multilingual applications. It includes the following topics:■■■Overview of UnicodeSQL NCHAR Data TypesUnicode String LiteralsSee Also:■■Oracle Database SQL Reference for information on SQLPL/SQL User's Guide and Reference for information on PL/SQL11.3.1 Overview of UnicodeUnicode is a universal encoded character set that enables you to store information inany language, using a single character set. Unicode provides a unique code value forevery character, regardless of the platform, program, or language.Unicode has the following advantages:■ It simplifies character set conversion and linguistic sort functions.■ It improves performance compared with native multibyte character sets.■ It supports the Unicode data type based on the Unicode standard.You can store Unicode characters in an Oracle database in two ways:■ You can create a Unicode database that enables you to store UTF-8 encodedcharacters as SQL CHAR data types.■11.3.2 SQL NCHAR Data TypesYou can support multilingual data in specific columns by using Unicode datatypes. You can store Unicode characters into columns of the SQL NCHAR data typesregardless of how the database character set has been defined. The NCHAR datatype is an exclusively Unicode data type.There are three SQL NCHAR data types:■ The NCHAR Data Type on page 11-20■ The NVARCHAR2 Data Type on page 11-20Working in a Global Environment 11-19
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Oracle SQL DeveloperOnline HelpRele
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Contents1 SQL Developer Concepts an
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3.12 Create/Edit Index ............
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6.3.2 Updating Data With the UPDATE
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10.2.5 SQL*Plus SET Commands.......
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SQL Developer User InterfaceThe men
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SQL Developer User InterfaceThe Com
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Database Objects1.2 Database Object
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Database Objectscontaining the mast
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Database Objects■■■■■■
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Database ConnectionsWhen you start
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Running and Debugging Functions and
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Using the SQL WorksheetRelated Topi
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Using the SQL WorksheetScript Runne
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Using the SQL Worksheetmentioned in
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Reports1.9 ReportsRelated TopicsRun
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Reports1.9.3 Table reportsTable rep
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Reportsissues and vulnerabilities,
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SQL Developer Preferencesand the SQ
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SQL Developer Preferences1.10.3 Cod
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SQL Developer PreferencesSQL Develo
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SQL Developer User Information: Loc
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Supplementary Oracle Database Infor
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Creating a Table (Books)the table t
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Creating a Table (Transactions)Colu
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Creating a SequenceName: for_key_bo
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Creating a PL/SQL Procedure2.6 Crea
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Using the SQL Worksheet for Queries
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Script for Creating and Using the L
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Script for Creating and Using the L
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Check for UpdatesTo remove the effe
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Select Library3.8 Select LibraryThi
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Create PL/SQL Function, Procedure,
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Create Table (quick creation)Relate
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Create/Edit Table (with advanced op
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Create Type (User-Defined)For more
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Create/Edit ViewTest Syntax: Checks
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Configure File Type AssociationsDia
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Find/Replace TextTo add a type of o
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Save/Save As3.37 Save/Save As3.38 S
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SQL*Plus Location3-28 SQL Developer
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Managing TablesTo include lowercase
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Managing Tables4.2.4 Column Constra
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Managing Indexes4.3 Managing Indexe
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Managing Indexesuseful when all of
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Managing Views4.4 Managing Views4.3
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Managing Synonyms4-12 SQL Developer
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Storing Numeric Data■■NCHAR and
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Storing Numeric DataThe absence of
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Storing Datetime Data5.4.1.2 Using
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Storing Datetime Data5-8 SQL Develo
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Retrieving Data With Queries■■
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Retrieving Data With QueriesSee Als
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Retrieving Data With QueriesSee Als
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Transaction Control Statements6.3.2
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Using Pseudocolumns, Sequences, and
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Using SQL Data Definition Language
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Using SQL Data Definition Language
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Entering and Executing PL/SQL CodeY
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Utilizing the Main Features of PL/S
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Page 142 and 143: Utilizing the Main Features of PL/S
Page 148 and 149: Handling PL/SQL ErrorsTo handle une
Page 150 and 151: Handling PL/SQL ErrorsIf you redecl
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Page 154 and 155: Overview of Packages and Subprogram
Page 156 and 157: Managing Packagescalling procedures
Page 158 and 159: Oracle Product-Specific PackagesTab
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Page 162 and 163: Oracle Product-Specific Packages8-1
Page 164 and 165: Overview of Triggers9.1.1 Types of
Page 166 and 167: Overview of Triggers■■A trigger
Page 168 and 169: Designing TriggersNote: A procedure
Page 170 and 171: Using SQL*Plus■■■Running Scri
Page 172 and 173: Using SQL*PlusA SQL script file is
Page 174 and 175: Using SQL*Plus10-6 SQL Developer On
Page 176 and 177: Overview of Globalization Support
Page 178 and 179: Setting up the Globalization Suppor
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Page 196 and 197: Locale-Dependent SQL Functions with
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Page 200 and 201: COLLECTION_IS_NULL exception, 7-22c
Page 202 and 203: overview, 7-14EXPLAIN PLANexecution
Page 204 and 205: NLSSORT SQL function, 11-21NO_DATA_
Page 206 and 207: displaying output from PL/SQL, 7-9s
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