Changes in Oracle Database Release 18c, Version 18.1

For Oracle Database 18c, Oracle Database PL/SQL Language Reference documents these new features.

New Features

Non-Persistance Support for Object Types

This feature enables you to mark abstract data types used in programs for processing only, for storage only, or for mixed use.

Instances of non-persistable types cannot persist on disk.

See Also:

  • CREATE TYPE statement [NOT] PERSISTABLE clause for more information about the syntax and semantics

Polymorphic Table Functions

A polymorphic table function (PTF) is a new type of table function whose return type is determined by the arguments passed into the PTF.

A table function is a function that returns a collection of rows and that can be called from the FROM clause of a SQL query block. 

The new polymorphic table function (PTF) provides an efficient and scalable framework to extend the analytical capabilities of the Oracle Database. A query writer is able to call these functions without knowing the details of the implementation of the PTF and the PTF doesn't need to know about the details or how the function is being executed (e.g. in serial or parallel) or whether the input rows are partitioned or ordered.

Therefore, a PTF is useful when SQL developers and database administrators want to provide generic extensions which work for arbitrary input tables or queries.

See Overview of Polymorphic Table Functions for more information.

Qualified Expressions

Aggregates and their necessary adjunct, qualified expressions, improve program clarity and programmer productivity.

Through Oracle Database 12c release 2, it was possible to supply the value of a non-scalar datatype with an expression, for example by using the type constructor for a nested table. Starting with Oracle Database Release 18c, any PL/SQL value can be provided by an expression (for example for a record or for an associative array) like a constructor provides an abstract datatype value. In PL/SQL, we use the terms "qualified expression" and "aggregate" rather than the SQL term "type constructor", but the functionality is the same.

See Qualified Expressions Overview and qualified_expression ::= for more information about the syntax and semantics.

Deprecated Features

The following features are deprecated in this release, and may be desupported in a future release.

The command ALTER TYPE ... INVALIDATE is deprecated. Use the CASCADE clause instead.

The REPLACE clause of ALTER TYPE is deprecated. Use the alter_method_spec clause instead. Alternatively, you can recreate the type using the CREATE OR REPLACE TYPE statement.

For the syntax and semantics, see ALTER TYPE Statement

Starting with Oracle Database 12c release 1 (12.1), the compilation parameter PLSQL_DEBUG is deprecated.

To compile PL/SQL units for debugging, specify PLSQL_OPTIMIZE_LEVEL=1.

For information about compilation parameters, see PL/SQL Units and Compilation Parameters.

Desupported Features

Some features previously described in this document are desupported in Oracle Database 12c release 2 (12.2).

  • Desupport of server-side SQLJ

    Oracle supports using client-side SQLJ. However, Oracle does not support the use of server-side SQLJ, including running stored procedures, types, functions, and triggers in the database environment.

See Also: