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PL/SQL User's Guide and Reference
10g Release 1 (10.1)

Part Number B10807-01
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What's New in PL/SQL?

This section describes new features of PL/SQL release 10g, and provides pointers to additional information.

The following sections describe the new features in PL/SQL:

New Features in PL/SQL for Oracle Database 10g

Release 1 (10.1)

Improved Performance

PL/SQL performance is improved across the board. Most improvements are automatic, with no action required from you.

Global optimization of PL/SQL code is controlled by the PLSQL_OPTIMIZE_LEVEL initialization parameter. The default optimization level improves performance for a broad range of PL/SQL operations. Most users should never need to change the default optimization level.

Performance improvements include better integer performance, reuse of expression values, simplification of branching code, better performance for some library calls, and elimination of dead code.

The new datatypes BINARY_FLOAT and BINARY_DOUBLE can improve performance in number-crunching applications, such as processing scientific data.

Native compilation is easier and more integrated, with fewer initialization parameters to set, less compiler configuration, the object code stored in the database, and compatibility with Oracle Real Application Clusters environments.

The FORALL statement can handle associate arrays and nested tables with deleted elements. You can now use this performance construct in more situations than before, and avoid the need to copy elements from one collection to another.

Enhancements to PL/SQL Native Compilation

This feature now requires less setup and maintenance.

A package body and its spec do not need to be compiled with the same setting for native compilation. For example, a package body can be compiled natively while the package spec is compiled interpreted, or vice versa.

Natively compiled subprograms are stored in the database, and the corresponding shared libraries are extracted automatically as needed. You do not need to worry about backing up the shared libraries, cleaning up old shared libraries, or what happens if a shared library is deleted accidentally.

The initialization parameters and command setup for native compilation have been simplified. The only required parameter is PLSQL_NATIVE_LIBRARY_DIR. The parameters related to the compiler, linker, and make utility have been obsoleted. The file that controls compilation is now a command file showing the commands and options for compiling and linking, rather than a makefile. Any errors that occur during native compilation are reflected in the USER_ERRORS dictionary view and by the SQL*Plus command SHOW ERRORS.

Native compilation is turned on and off by a separate initialization parameter, PLSQL_CODE_TYPE, rather than being one of several options in the PLSQL_COMPILER_FLAGS parameter, which is now deprecated.

FORALL Support for Non-Consecutive Indexes

You can use the INDICES OF and VALUES OF clauses with the FORALL statement to iterate over non-consecutive index values. For example, you can delete elements from a nested table, and still use that nested table in a FORALL statement.

New IEEE Floating-Point Types

New datatypes BINARY_FLOAT and BINARY_DOUBLE represent floating-point numbers in IEEE 754 format. These types are useful for scientific computation where you exchange data with other programs and languages that use the IEEE 754 standard for floating-point. Because many computer systems support IEEE 754 floating-point operations through native processor instructions, these types are efficient for intensive computations involving floating-point data.

Support for these types includes numeric literals such as 1.0f and 3.141d, arithmetic operations including square root and remainder, exception handling, and special values such as not-a-number (NaN) and infinity.

The rules for overloading subprograms are enhanced, so that you can write math libraries with different versions of the same function operating on PLS_INTEGER, NUMBER, BINARY_FLOAT, and BINARY_DOUBLE parameters.

Improved Overloading

You can now overload subprograms that accept different kinds of numeric arguments, to write math libraries with specialized versions of each subprogram for different datatypes.

Nested Table Enhancements

Nested tables defined in PL/SQL have many more operations than previously. You can compare nested tables for equality, test whether an element is a member of a nested table, test whether one nested table is a subset of another, perform set operations such as union and intersection, and much more.

Compile-Time Warnings

Oracle can issue warnings when you compile subprograms that produce ambiguous results or use inefficient constructs. You can selectively enable and disable these warnings through the PLSQL_WARNINGS initialization parameter and the DBMS_WARNING package.

Quoting Mechanism for String Literals

Instead of doubling each single quote inside a string literal, you can specify your own delimiter character for the literal, and then use single quotes inside the string.

See Also:

Implicit Conversion Between CLOB and NCLOB

You can implicitly convert from CLOB to NCLOB or from NCLOB to CLOB. Because this can be an expensive operation, it might help maintainability to continue using the TO_CLOB and TO_NCLOB functions.

Regular Expressions

If you are familiar with UNIX-style regular expressions, you can use them while performing queries and string manipulations. You use the REGEXP_LIKE operator in SQL queries, and the REGEXP_INSTR, REGEXP_REPLACE, and REGEXP_SUBSTR functions anywhere you would use INSTR, REPLACE, and SUBSTR.

Flashback Query Functions

The functions SCN_TO_TIMESTAMP and TIMESTAMP_TO_SCN let you translate between a date and time, and the system change number that represents the database state at a point in time.

New Features in PL/SQL for Oracle9i

Release 2 (9.2)

Release 1 (9.0.1)