Database Reference
In-Depth Information
Expressions and the new EVALUATE operator permit what would
previously have been multiple-line SQL statements to be placed into
a single line of SQL or PL/SQL code. The term used by Oracle docu-
mentation is “describing user's interest in data” (see Chapter 14).
The Oracle Expression Filter uses an Expression datatype and the
EVALUATE operator. The EVALUATE operator allows concise
conditional expression evaluation.
Portable operating system interface (POSIX) standard regular
expression capabilities allow search-and-replace functionality with
changes to the LIKE operator, REPLACE, and INSTR functions.
This search-and-replace capability is equivalent to search-and-
replace power in Unix scripting languages or something like the
SED editor or when using Perl.
2.1.2
PL/SQL Improvements in Oracle Database 10g
An intense examination of the details of PL/SQL is not required in an SQL
reference-type topic, so some of the items listed here are not covered in this
topic. However, a basic introduction to PL/SQL programming is covered in
Chapter 24.
Everything possible in Oracle SQL with respect to SQL coding can
now be coded and executed from within PL/SQL. PL/SQL is now
fully syntactically equivalent with Oracle SQL. In other words, all
Oracle SQL commands can be coded into PL/SQL scripts.
The PL/SQL compiler is better optimized including bulk binding
and native compilation. Native compilation stores PL/SQL units in
BLOB objects as a compiled binary form. Previously, PL/SQL was
interpreted PL/SQL code. Interpretation implies compilation or con-
version to binary at run-time; in the case of PL/SQL, coded com-
mands were read and parsed for every execution. Binary compilation
simply executes binary code at run-time and is therefore potentially
much quicker to execute.
Using binary datatypes can help number-crunching performance.
Note:
Number crunching or heavily computational code should not really
be constructed using a language such as PL/SQL. Java or even C is better
suited, and most commonly at the application level.
