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Oracle PL/SQL Tutorial - An Introduction to PL/SQL (Part 3)
Our third Oracle PLSQL tutorial introduces the data types and language elements.
Oracle PLSQL Data Types
PLSQLis a block-structured language like Ada and the built-in scalar datatypes include all the SQL data
types plus Boolean and integer types as well as some additional sub types. The standard PL/SQL data types
can also be extended by defining your own types (not to be confused with types declared in the database)
in the form of records and PLSQL collections.
PLS_INTEGER - signed integer type using machine
BINARY_INTEGER - identical to PLS_INTEGER
SIMPLE_INTEGER - same as PLS_INTEGER
type but with an added NOT NULL constraint
Numeric variables are usually declared as NUMBER, with a
scale and precision if necessary, for compatibility with the
SQL datatypes or as PLS_INTEGER for efficiency in
Variables defined as Boolean can have one of 3 values: true, false or NULL (undefined)
Oracle PL/SQL Language Elements
As PL/SQL is modeled on Ada, it uses a different syntax to C or Java but the language constructs are
common to all modern high-level languages..
numeric FOR loops
cursor FOR loops (these act on the results of queries)
Conditional and sequential control statements
IF ... THEN ... END IF and IF ... THEN ... ELSE ... END IF
GOTO (but the use of this is usually not necessary)
simple and searched CASE statements
Assignment and Expression comparison statements
These types of statements are the major difference between PL/SQL and C/C++/Java. In Java/C/C++ the
assignment operator is the single "=" and the comparison operator is "==" (i.e. 2 "=" signs together)
whereas in PL/SQL, Ada, Modula-2 and Pascal, the single "=" is used as the comparison operator and ":="
is used as the assignment operator.
On top of the normal language elements, the tight integration with Oracle allows SQL statements to be
embedded directly in PL/SQL programs and PL/SQL functions to be called directly from SQL.
Oracle PLSQL tutorial Part 2 Oracle PLSQL tutorial Part 4
To extend and enhance your knowledge of PL/SQL quickly why not consider a formal training course? We
offer instructor-led training courses at centres across the country. See the Oracle training page for details of
our scheduled courses or contact us for more information.
Looking to sky-rocket productivity, save time and reduce costs?
Training is a highly cost-effective and proven method of boosting productivity. Smartsoft offers instructor-
led training in Oracle and related technologies on or off site in cities across the UK as well as self-study
online training. See our scheduled Oracle training courses, or let us know your requirements.
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