Oracle® Database Programmer's Guide to the Oracle Precompilers 12c Release 2 (12.2) E85800-01 January 2017 Oracle Database Programmer's Guide to the Oracle Precompilers, 12c Release 2 (12.2) E85800-01 Copyright © 2008, 2017, Oracle and/or its affiliates. All rights reserved. Primary Author: Siddharth Naidu Contributors: Denis Raphaely, Simon Watt, Radhakrishnan Hari, Nancy Ikeda, Ken Jacobs, Valarie Moore, Tim Smith, Scott Urman, Arun Desai, Mallikharjun Vemana, Subhranshu Banerjee This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. 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Contents Preface Intended Audience xxiii Structure xxiii Documentation Accessibility xxv Related Documents xxvi Conventions xxvi 1 Getting Acquainted 1.1 What Is an Oracle Precompiler? 1-1 1.1.1 Language Alternatives 1-2 1.2 Why Use an Oracle Precompiler? 1-3 1.3 Why Use SQL? 1-3 1.4 Why Use PL/SQL? 1-4 1.5 What Do the Oracle Precompilers Offer? 1-4 1.6 Do the Oracle Precompilers Meet Industry Standards? 1-5 1.6.1 Requirements 1-6 1.6.2 Compliance 1-6 1.6.3 FIPS Flagger 1-6 1.6.4 FIPS Option 1-7 1.6.5 Certification 1-7 2 Learning the Basics 2.1 Key Concepts of Embedded SQL Programming 2-1 2.1.1 Embedded SQL Statements 2-1 2.1.2 Executable versus Declarative Statements 2-2 2.1.3 Embedded SQL Syntax 2-3 2.1.4 Static versus Dynamic SQL Statements 2-4 2.1.5 Embedded PL/SQL Blocks 2-4 2.1.6 Host and Indicator Variables 2-4 2.1.7 Oracle Datatypes 2-5 2.1.8 Arrays 2-5 iii 2.1.9 Datatype Equivalencing 2-5 2.1.10 Private SQL Areas, Cursors, and Active Sets 2-5 2.1.11 Transactions 2-6 2.1.12 Errors and Warnings 2-6 2.2 Steps in Developing an Embedded SQL Application 2-7 2.3 A Sample Program 2-9 2.4 Sample Tables 2-10 2.4.1 Sample Data 2-10 3 Meeting Program Requirements 3.1 The Declare Section 3-1 3.1.1 An Example 3-2 3.2 INCLUDE Statements 3-2 3.3 The SQLCA 3-3 3.4 Oracle Datatypes 3-3 3.4.1 Internal Datatypes 3-4 3.4.2 CHAR 3-4 3.4.3 DATE 3-5 3.4.4 LONG 3-5 3.4.5 LONG RAW 3-5 3.4.6 MLSLABEL 3-5 3.4.7 NUMBER 3-6 3.4.8 RAW 3-6 3.4.9 ROWID 3-6 3.4.10 VARCHAR2 3-6 3.4.11 SQL Pseudocolumns and Functions 3-7 3.4.12 ROWLABEL Column 3-8 3.4.13 External Datatypes 3-8 3.4.14 CHAR 3-9 3.4.15 CHARF 3-10 3.4.16 CHARZ 3-10 3.4.17 DATE 3-10 3.4.18 DECIMAL 3-11 3.4.19 DISPLAY 3-11 3.4.20 FLOAT 3-11 3.4.21 INTEGER 3-11 3.4.22 LONG 3-11 3.4.23 LONG RAW 3-11 3.4.24 LONG VARCHAR 3-12 3.4.25 LONG VARRAW 3-12 iv 3.4.26 MLSLABEL 3-12 3.4.27 NUMBER 3-12 3.4.28 RAW 3-13 3.4.29 ROWID 3-13 3.4.30 STRING 3-13 3.4.31 UNSIGNED 3-14 3.4.32 VARCHAR 3-14 3.4.33 VARCHAR2 3-14 3.4.34 VARNUM 3-15 3.4.35 VARRAW 3-15 3.5 Datatype Conversion 3-15 3.5.1 DATE Values 3-17 3.5.2 RAW and LONG RAW Values 3-17 3.6 Declaring and Referencing Host Variables 3-17 3.6.1 Some Examples 3-18 3.6.2 VARCHAR Variables 3-18 3.6.3 Host Variable Guidelines 3-19 3.7 Declaring and Referencing Indicator Variables 3-19 3.7.1 INDICATOR Keyword 3-19 3.7.2 An Example 3-19 3.7.3 Indicator Variable Guidelines 3-20 3.8 Datatype Equivalencing 3-20 3.8.1 Why Equivalence Datatypes? 3-20 3.8.2 Host Variable Equivalencing 3-21 3.8.3 An Example 3-22 3.8.4 About Using the CHARF Datatype Specifier 3-23 3.8.5 Guidelines 3-23 3.9 Globalization Support 3-24 3.10 Multibyte Globalization Support Character Sets 3-26 3.10.1 Character Strings in Embedded SQL 3-26 3.10.2 Dynamic SQL 3-26 3.10.3 Embedded DDL 3-26 3.10.4 Multibyteultibyte Globalization Support Host Variables 3-26 3.10.5 Restrictions 3-27 3.10.6 Blank Padding 3-27 3.10.7 Indicator Variables 3-27 3.11 Concurrent Logons 3-27 3.11.1 Some Preliminaries 3-28 3.11.2 Default Databases and Connections 3-28 3.11.3 Explicit Logons 3-29 3.11.4 Single Explicit Logons 3-29 v 3.11.5 Multiple Explicit Logons 3-32 3.11.6 Implicit Logons 3-33 3.11.7 Single Implicit Logons 3-33 3.11.8 Multiple Implicit Logons 3-34 3.12 Embedding OCI (Oracle Call Interface) Calls 3-34 3.12.1 About Setting Up the LDA 3-35 3.12.2 Remote and Multiple Connections 3-35 3.13 About Developing X/Open Applications 3-35 3.13.1 Oracle-Specific Issues 3-36 3.13.2 About Connecting to Oracle 3-37 3.13.3 Transaction Control 3-37 3.13.4 OCI Calls 3-37 3.13.5 Linking 3-37 4 Using Embedded SQL 4.1 About Using Host Variables 4-1 4.1.1 Output versus Input Host Variables 4-1 4.2 About Using Indicator Variables 4-2 4.2.1 Input Variables 4-2 4.2.2 Output Variables 4-2 4.2.3 Inserting Nulls 4-3 4.2.4 Handling Returned Nulls 4-3 4.2.5 Fetching Nulls 4-3 4.2.6 Testing for Nulls 4-4 4.2.7 Fetching Truncated Values 4-4 4.3 The Basic SQL Statements 4-4 4.3.1 Selecting Rows 4-5 4.3.2 Available Clauses 4-6 4.3.3 Inserting Rows 4-6 4.3.4 Using Subqueries 4-6 4.3.5 Updating Rows 4-6 4.3.6 Deleting Rows 4-7 4.3.7 Using the WHERE Clause 4-7 4.4 Cursors 4-7 4.4.1 Declaring a Cursor 4-8 4.4.2 Opening a Cursor 4-8 4.4.3 Fetching from a Cursor 4-9 4.4.4 Closing a Cursor 4-10 4.4.5 Using the CURRENT OF Clause 4-10 4.4.6 Restrictions 4-10 vi 4.4.7 A Typical Sequence of Statements 4-11 4.4.8 A Complete Example 4-11 4.5 Cursor Variables 4-12 4.5.1 About Declaring a Cursor Variable 4-13 4.5.2 Allocating a Cursor Variable 4-13 4.5.3 Opening a Cursor Variable 4-13 4.5.4 Fetching from a Cursor Variable 4-14 4.5.5 Closing a Cursor Variable 4-15 5 Using Embedded PL/SQL 5.1 Advantages of PL/SQL 5-1 5.1.1 Better Performance 5-1 5.1.2 Integration with Oracle 5-1 5.1.3 Cursor FOR Loops 5-2 5.1.4 Subprograms 5-2 5.1.5 Parameter Modes 5-3 5.1.6 Packages 5-3 5.1.7 PL/SQL Tables 5-3 5.1.8 User-defined Records 5-4 5.2 About Embedding PL/SQL Blocks 5-5 5.3 About Using Host Variables 5-5 5.3.1 An Example 5-5 5.3.2 A More Complex Example 5-6 5.3.3 VARCHAR Pseudotype 5-8 5.4 About Using Indicator Variables 5-8 5.4.1 Handling Nulls 5-9 5.4.2 Handling Truncated Values 5-9 5.5 About Using Host Arrays 5-10 5.5.1 ARRAYLEN Statement 5-11 5.6 About Using Cursors 5-12 5.6.1 An Alternative 5-13 5.7 Stored Subprograms 5-13 5.7.1 Creating Stored Subprograms 5-14 5.7.2 Calling a Stored Subprogram 5-15 5.7.3 Remote Access 5-17 5.7.4 Getting Information about Stored Subprograms 5-17 5.8 About Using Dynamic PL/SQL 5-18 5.8.1 Restriction 5-18 vii 6 Running the Oracle Precompilers 6.1 The Precompiler Command 6-1 6.2 What Occurs during Precompilation? 6-2 6.3 Precompiler Options 6-2 6.3.1 Default Values 6-3 6.3.2 Determining Current Values 6-4 6.3.3 Case Sensitivity 6-4 6.3.4 Configuration Files 6-4 6.4 Entering Options 6-5 6.4.1