What's New in PL/SQL?

This section describes new features of PL/SQL release 9.0.1 and provides pointers to additional information.

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

• Oracle9i New Features in PL/SQL

Oracle9i New Features in PL/SQL

• Integration of SQL and PL/SQL parsers

  PL/SQL now supports the complete range of syntax for SQL statements, such as INSERT, UPDATE, DELETE, and so on. If you received errors for valid SQL syntax in PL/SQL programs before, those statements should now work.

  See Also: Because of more consistent error-checking, you might find that some invalid code is now found at compile time instead of producing an error at runtime, or vice versa. You might need to change the source code as part of the migration procedure. See Oracle9i Database Migration for details on the complete migration procedure.

• CASE statements and expressions

  CASE statements and expressions are a shorthand way of representing IF/THEN choices with multiple alternatives.

  See Also: "CASE Expressions" "CASE Statement" "CASE Statement"

• Inheritance and Dynamic Method Dispatch

  Types can be declared in a supertype/subtype hierarchy, with subtypes inheriting attributes and methods from their supertypes. The subtypes can also add new attributes and methods, and override existing methods. A call to an object method executes the appropriate version of the method, based on the type of the object.

  See Also: "Overview of PL/SQL Type Inheritance" "How Overloading Works with Inheritance"

• Type Evolution

  Attributes and methods can be added to and dropped from object types, without the need to re-create the types and corresponding data. This feature lets the type hierarchy adapt to changes in the application, rather than being planned out entirely in advance.

  See Also: "Changing Attributes and Methods of an Existing Object Type (Type Evolution)"

• New Date/Time Types

  The new datatype TIMESTAMP records time values including fractional seconds. New datatypes TIMESTAMP WITH TIME ZONE and TIMESTAMP WITH LOCAL TIME ZONE allow you to adjust date and time values to account for time zone differences. You can specify whether the time zone observes daylight savings time, to account for anomalies when clocks shift forward or backward. New datatypes INTERVAL DAY TO SECOND and INTERVAL YEAR TO MONTH represent differences between two date and time values, simplifying date arithmetic.

  See Also: "Datetime and Interval Types" "Datetime and Interval Arithmetic" "Datetime Literals"

• Native Compilation of PL/SQL Code

  Improve performance by compiling Oracle-supplied and user-written stored procedures into native executables, using typical C development tools. This setting is saved so that the procedure is compiled the same way if it is later invalidated.

  See Also: "Compiling PL/SQL Code for Native Execution"

• Improved Globalization and National Language Support

  Data can be stored in Unicode format using fixed-width or variable-width character sets. String handling and storage declarations can be specified using byte lengths, or character lengths where the number of bytes is computed for you. You can set up the entire database to use the same length semantics for strings, or specify the settings for individual procedures; this setting is remembered if a procedure is invalidated.

  See Also: "Character Types" "National Character Types"

• Table Functions and Cursor Expressions

  You can query a set of returned rows like a table. Result sets can be passed from one function to another, letting you set up a sequence of transformations with no table to hold intermediate results. Rows of the result set can be returned a few at a time, reducing the memory overhead for producing large result sets within a function.

  See Also: "Accepting and Returning Multiple Rows with Table Functions" "Using Cursor Expressions"

• Multilevel Collections

  You can nest the collection types, for example to create a VARRAY of PL/SQL tables, a VARRAY of VARRAYs, or a PL/SQL table of PL/SQL tables. You can model complex data structures such as multidimensional arrays in a natural way.

  See Also: "Using Multilevel Collections"

• Better Integration for LOB Datatypes

  You can operate on LOB types much like other similar types. You can use character functions on CLOB and NCLOB types. You can treat BLOB types as RAWs. Conversions between LOBs and other types are much simpler, particularly when converting from LONG to LOB types.

  See Also: "LOB Types"

• Enhancements to Bulk Operations

  You can now perform bulk SQL operations, such as bulk fetches, using native dynamic SQL (the EXECUTE IMMEDIATE statement). You can perform bulk insert or update operations that continue despite errors on some rows, then examine the problems after the operation is complete.

  See Also: "Reducing Loop Overhead for Collections with Bulk Binds" "Using Bulk Dynamic SQL" "EXECUTE IMMEDIATE Statement"

• MERGE Statement

  This specialized statement combines insert and update into a single operation. It is intended for data warehousing applications that perform particular patterns of inserts and updates.

  See Also: "MERGE Statement" for a brief discussion and example Oracle9i SQL Reference for detailed information