New Stuff in the Oracle PL/SQL Language

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New(er) Stuff in PL/SQL
Steven Feuerstein, Oracle Developer Advocate
1

What’s Included
Autonomous
Database
2 x Databases
20GB Storage Each
Load
Balancing
10 Mbps
Bandwidth
Shape
Storage
2 x 50GB Block
10GB Object
10GB Archive
Compute
2 x VM
1GB Memory
Each
demo

A Roundup of New PL/SQL Features
18c Qualified expressions for collections and records
Whitelisting with the ACCESSIBLE_BY Clause
More PL/SQL-Only Data Types Cross PL/SQL-to-SQL Interface
Optimizing Function Execution in SQL
The UTL_CALL_STACK Package
Privileges/Access Management for Program Units
Static Expressions In Place of Literals
Marking elements for deprecation
PL/Scope now includes SQL statements in its analysis

How to get this presentation and code
Go to slideshare.net, search "pl/sql
new stuff". View or download the
presentation.
Code referenced in file names:
download this zip…
http://bit.ly/sfdemofiles

Qualified Expressions (Constructors) for
Associative Arrays and Records
In-line assignment of values to our user-defined types!
Nice improvement in developer productivity and code simplicity
DECLARE
TYPE ints_t IS TABLE OF INTEGER
INDEX BY PLS_INTEGER;
l_ints ints_t := ints_t (
1 => 55, 2 => 555, 3 => 5555);
BEGIN
...
END;
DECLARE
TYPE ints_t IS TABLE OF INTEGER
INDEX BY PLS_INTEGER;
l_ints;
BEGIN
l_ints (1) := 55;
l_ints (2) := 555;
l_ints (3) := 5555;
...
END;

PL/Scope: powerful code analysis tool
This compiler-driven tool collects information about identifiers and
statements, and stores it in data dictionary views.
As of 12.2, this includes analysis of SQL statements inside your PL/SQL
code.
Use PL/Scope to answer questions like:
Where is a variable assigned a value in a program?
Which subprograms call another subprogram?
Which SQL statements appear more than once in my application?
Where do inserts, updates, deletes occur against a specific table?

The ACCESSIBLE_BY Clause 12.1
ACCESSIBLE_BY extends the concept of "privacy" for package
subprograms.
Use it to define a "whitelist" of program units that can invoke a
package's subprograms.
When that public procedure really shouldn’t be used
12c_accessible_by.sql
PACKAGE private_pkg
ACCESSIBLE BY (public_pkg)
IS
PROCEDURE do_this;
PROCEDURE do_that;
END;
PACKAGE BODY public_pkg
IS
PROCEDURE do_only_this
IS
BEGIN
private_pkg.do_this;
private_pkg.do_that;
END;
END;

More PL/SQL-Only Data Types Cross
PL/SQL-to-SQL Interface
Prior to 12c, PL/SQL-only datatypes could not be bound in dynamic
SQL statements, restricted what functions could be called in SQL, etc.
Now, those constraints are greatly relaxed.
Bind records and associative arrays
Use TABLE operator with associative arrays
Can bind Booleans with dynamic PL/SQL, but you cannot bind Booleans into
SQL statements.
TABLE with associative arrays!
12c_table*.sql 12c_bind*.sql

Optimizing Function Execution in SQL
That seems like an awfully good idea!
Two methods:
WITH clause that defines a function
UDF pragma that gives more options to the compiler
WITH FUNCTION: define a function directly within your SQL
statement.
Say goodbye to nasty context switch!
For all those user-defined functions
12c_with_function*.sql 12c_udf*.sql

The UTL_CALL_STACK Package
Prior to 12c, you could obtain several kinds of "stacks" through
individual function calls:
DBMS_UTILITY.FORMAT_CALL_STACK - "How did I get here?"
DBMS_UTILITY.FORMAT_ERROR_STACK - "What is the error
message/stack?"
DBMS_UTILITY.FORMAT_ERROR_BACKTRACE - "On what line was my error
raised?"
Now, the UTL_CALL_STACK package supports all that and a much
better API to the info in the stack.
Improved execution stack granularity and more
12c_utl_call_stack*.sql

Static Expressions In Place of Literals
Static PL/SQL expressions are allowed where only literals were
allowed.
You no longer have to hard-code maximum lengths for VARCHAR2
variables and other data types.
You can even use the built-in ORA_MAX_NAME_LEN for the new
extended name lengths.
No more VARCHAR2(32767)!
IS
my_big_var VARCHAR2 (ORA_MAX_NAME_LEN + 2);
my_qualified_var VARCHAR2 (2 * (ORA_MAX_NAME_LEN +2) + 1);
BEGIN
my_big_var := '"Table_Name";
my_qualified_var := "Schema_Name"."Table_Name";
122_expressions.sql

Goodbye, "Tiny" Name Lengths!
Instead of 30 bytes you can now go all the way up to 128.
But this doesn't mean you should.
Most beneficial for:
Migrations from other databases to Oracle
Multi-byte character sets
Being able to squeak just over that 30 character barrier and no longer having
to compromise readability
Now your identifiers can go on_and_on_and_on_and_on_and_on_and...
122_long_identifiers.sql

Goodbye, Tiny SQL VARCHAR2!
It sure has been irritating that PL/SQL supports VARCHAR2s up to
32K in size (after which , you must switch over to CLOBs), while in
SQL, the maximum was 4000.
Now, SQL's VARCHAR2 and NVARCHAR2 have been extended to 32K
as well!
Note: SQL has these maximum sizes only if the MAX_STRING_SIZE
initialization parameter is set to EXTENDED.
And one more impedance between PL/SQL and SQL
12c_sql_varchar2.sql

Kill Off Old, Dead (should be Zombie) Code.
In 12.2, you can now document via a pragma code that has been
deprecated.
You can then use compile-time warnings to:
identify usages of deprecated code
make it impossible to compile program units that use deprecated code
But don't make PLW-06019 an error. That simply documents the use
of the pragma.
But how do you find it?
CREATE OR REPLACE PACKAGE old_pkg AUTHID DEFINER
AS
PRAGMA DEPRECATE (old_pkg, 'Use new_pkg instead!');
PROCEDURE proc;
END;

Grant Roles to Program Units (back to 12.1)
Grant roles to program units, so you fine-tune the privileges available
to the invoker of a program unit.
Helpful when you don't want the invoker to inherit all of the definer's
privileges.
Roles granted to a program unit do not affect compilation.
Instead, they affect the privilege checking of SQL statements that the unit
issues at run time.
Unit executes with privileges of both its own roles and any other currently
enabled roles.
Nice usability enhancement
12c_grant_role_units.sql 12c_roles_for_program_units.sql
Most helpful when unit executing dynamic SQL

BEQUEATH CURRENT_USER for Views
Prior to 12.1, if your view executed a function, it would always be run
under the privileges of the view's owner, and not that of the function.
Even if the function was defined with AUTHID CURRENT_USER
Add the BEQUEATH CURRENT_USER clause and then the invoker
right's mode of the function will be "honored."
Tying up a loose end
12c_bequeath.sql

INHERIT PRIVILEGES and INHERIT ANY PRIVILEGES
More fine-tuning for privilege management!
You can override AUTHID and BEQUEATH settings by revoking
INHERIT PRIVILEGES.
On a schema-level basis
You can say, in effect: "All schemas but SCOTT can use my privileges
when running X."
After upgrade, all works as before.
INHERT PRIVILEGES granted to all schemas
Yes, there’s more!
12c_inherit_privileges.sql

And is that it?
Support for JSON in PL/SQL via new pre-defined JSON types
Block code coverage
Improvements to DBMS_HPROF, the hierarchical profiler
DBMS_SQL support for PL/SQL types
No, there's more, but there's no more time.

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