Release 8.1.6
Part Number A76951-01
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| Pro*COBOL Precompiler Programmer's Guide Release 8.1.6 Part Number A76951-01 |
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This manual is a comprehensive user's guide and reference to the Oracle Pro*COBOL Precompiler. It shows you how to develop COBOL programs that use the database languages SQL and PL/SQL to access and manipulate Oracle data. See Oracle8i SQL Reference and PL/SQL User's Guide and Reference for more information on SQL and PL/SQL.
This preface covers these topics:
This manual shows you how the Oracle Pro*COBOL Precompiler and embedded SQL can benefit your entire applications development process. It gives you lessons in how to design and develop applications that harness the power of Oracle. And, as quickly as possible, it helps you become proficient in writing embedded SQL programs.
An important feature of this manual is its emphasis on getting the most out of Pro*COBOL and embedded SQL. To help you master these tools, this manual shows you all the "tricks of the trade" including ways to improve program performance. It also includes many program examples to better your understanding and demonstrate the usefulness of embedded SQL.
Note: You will not find installation instructions or system-specific information in this manual. For that kind of information, refer to your system-specific Oracle documentation.
For information about migrating your applications from Oracle7 to Oracle8i, see Oracle8i Migration.
Anyone developing new COBOL applications or converting existing applications to run in the Oracle8i environment will benefit from reading this manual. Written especially for programmers, this comprehensive treatment of Pro*COBOL will also be of value to systems analysts, project managers, and others interested in embedded SQL applications.
To use this manual effectively, you need a working knowledge of the following subjects:
A brief summary of what you will find in each chapter and appendix follows.
This chapter introduces you to Pro*COBOL. You look at its role in developing application programs that manipulate Oracle data and find out what are its key benefits and features.
Chapter 2, "Precompiler Concepts"
This chapter explains how embedded SQL programs work. Then the guidelines for programming in Pro*COBOL are presented. Compilation issues are discussed and the sample Oracle tables used in this guide are presented, as is the first of the demo programs, SAMPLE1.PCO.
Chapter 3, "Database Concepts"
This chapter describes transaction processing. You learn the basic techniques that safeguard the consistency of your database. You then learn how to connect to a database and how to connect to multiple distributed databases.
Chapter 4, "Datatypes and Host Variables"
The internal and external datatypes are defined at length. Then you are shown how to use the datatypes in your COBOL program. Then runtime contexts and ROWIDs are explained, followed by National Language Support, datatype conversion and datatype equivalencing. (with a sample program).
This chapter teaches you the essentials of embedded SQL programming. You learn how to use host variables, indicator variables, cursors, cursor variables, and the fundamental SQL commands that insert, update, select, and delete Oracle data.
This chapter shows you how to improve performance by embedding PL/SQL transaction processing blocks in your program. You learn how to use PL/SQL with host variables, indicator variables, cursors, stored subprograms in either PL/SQL or Java, host tables, and dynamic PL/SQL.
This chapter looks at using host (COBOL) tables to improve program performance. You learn how to manipulate Oracle data using tables, how to operate on all the elements of a table with a single SQL statement, and how to limit the number of table elements processed.
Chapter 8, "Error Handling and Diagnostics"
This chapter provides an in-depth discussion of error reporting and recovery. You learn how to detect and handle errors using the status variable SQLSTATE, the SQLCA structure, and the WHENEVER statement. You also learn how to diagnose problems using the ORACA.
Chapter 9, "Oracle Dynamic SQL"
This chapter shows you how to take advantage of dynamic SQL. You are taught three methods, from simple to complex, for writing flexible programs that let users build SQL statements interactively at run time.
Chapter 10, "ANSI Dynamic SQL"
ANSI Dynamic SQL, Method 4, is presented. This method supports all Oracle datatypes, while the older Oracle Method 4 does not support cursor variables, tables of group items, DML Returning Clause, and LOBs. ANSI Method 4 uses embedded SQL statements that set up descriptor areas in memory. ANSI SQL should be used for all new applications.
Chapter 11, "Oracle Dynamic SQL: Method 4"
This chapter shows you how to maintain existing applications that use dynamic SQL Method 4. Numerous examples are used to illustrate the method.
Chapter 12, "Multithreaded Applications"
Writing multithreaded applications is discussed in this chapter. Your compiler must also support multithreading.
Chapter 13, "Large Objects (LOBs)"
This chapter presents large object datatypes (BLOBs, CLOBs, NCLOBs, and BFILEs). The embedded SQL commands that provide functionality comparable to OCI and PL/SQl are presented and used in sample code.
Chapter 14, "Precompiler Options"
This chapter details the requirements for running the Pro*COBOL precompiler, and a list of the precompiler options. You learn what happens during precompilation, how to issue the Pro*COBOL command, and how to specify the many useful precompiler options.
This appendix highlights the improvements and new features introduced with both releases 8.1 and 8.0 of Pro*COBOL.
Appendix B, "Operating System Dependencies"
Some details of Pro*COBOL programming vary from one system to another. So, you are occasionally referred to other manuals for system-specific information. For convenience, this appendix collects all such external issues.
Appendix C, "Reserved Words, Keywords, and Namespaces"
This appendix refers you to a table of reserved words that have a special meaning to Pro*COBOL. The namespaces that are reserved for Oracle libraries are presented.
Appendix D, "Performance Tuning"
This appendix gives you some simple methods for improving the performance of your applications.
Appendix E, "Syntactic and Semantic Checking"
This appendix shows you how to use the SQLCHECK option to control the type and extent of syntactic and semantic checking done on embedded SQL statements and PL/SQL blocks.
Appendix F, "Embedded SQL Statements and Precompiler Directives"
This appendix contains descriptions of precompiler directives, embedded SQL commands, and Oracle embedded SQL extensions. The purpose, prerequisites, syntax diagrams, keywords, parameters, usage notes, examples, and related topics are presented for each statement and directive.
Note: The former chapter 12, "User Exits" has been omitted from this release.
Important terms being defined for the first time are italicized. In discussions, UPPER CASE is used for database objects, precompiler options, and SQL keywords. Variables and constants are in monospaced font, as are code samples.
The following notation is used in this manual:
Embedded SQL syntax is described using a variant of Backus-Naur Form (BNF), which includes the following symbols:
This manual provides several Pro*COBOL programs to help you in writing your own. These programs illustrate the key concepts and features of Pro*COBOL programming and demonstrate techniques that let you take full advantage of SQL's power and flexibility.
Each complete sample program in this manual is available on-line in the demo directory. However, the exact filenames are system-dependent. For exact filenames, see your Oracle system-specific documentation. We present sample code developed for the Solaris operating system in this manual.
SQL has become the standard language for relational database management systems. This section describes how the Pro*COBOL Precompiler conforms to the latest SQL standards established by the following organizations:
Those organizations have adopted SQL as defined in the following publications:
ANSI X3.135-1992 (known informally as SQL92) specifies a "conforming SQL language" and, to allow implementation in stages, defines three language levels:
A conforming SQL implementation must support at least Entry SQL.
ANSI X3.168-1992 specifies the syntax and semantics for embedding SQL statements in application programs written in a standard programming language such as COBOL-74 and COBOL-85.
ISO/IEC 9075-1992 fully adopts the ANSI standards.
FIPS PUB 127-2, which applies to RDBMS software acquired for federal use, also adopts the ANSI/ISO standards. In addition, it specifies minimum sizing parameters for database constructs and requires a "FIPS Flagger" to identify ANSI extensions.
For copies of the ANSI standards, write to
For a copy of the ISO standard, write to the national standards office of any ISO participant. For a copy of the NIST standard, write to
The Pro*COBOL precompiler complies 100% with the ANSI, ISO, and NIST standards. As required, they support Entry SQL and provide a FIPS Flagger.
According to FIPS PUB 127-1:
"An implementation that provides additional facilities not specified by this standard shall also provide an option to flag nonconforming SQL language or conforming SQL language that may be processed in a nonconforming manner."
To meet this requirement, the Pro*COBOL Precompiler provides the FIPS Flagger, which flags ANSI extensions. An extension is any SQL element that violates ANSI format or syntax rules, except privilege enforcement rules. For a list of Oracle extensions to standard SQL, see the Oracle8i SQL Reference.
You can use the FIPS Flagger to identify
Thus, the FIPS Flagger helps you develop portable applications.
An option named FIPS governs the FIPS Flagger. To enable the FIPS Flagger, you specify FIPS=YES inline or on the command line. For more information about the command-line option FIPS, see "FIPS".
NIST tested the Pro*COBOL Precompiler for ANSI Entry SQL compliance using the SQL Test Suite, which consists of nearly 300 test programs. Specifically, the programs tested for conformance to the COBOL embedded SQL standards. As a result, the Pro*COBOL Precompiler was certified 100% ANSI-compliant.
For more information about the tests, write to
The Pro*COBOL Precompiler provides National Language Support (NLS) of multi-byte character data by complying with the Multivendor Integration Architecture (MIA) specification, Version 1.3, and the Service Providers Integrated Requirements for Information Technology (SPIRIT) specification, Issue 2.
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