In this tutorial, you'll learn the difference between delete/drop and truncate.
PL/SQL (Procedural Language/Structured Query Language) is Oracle Corporation's procedural extension for SQL and the Oracle relational database. PL/SQL is available in Oracle Database (since version 7), TimesTen in-memory database (since version 11.2.1), and IBM DB2 (since version 9.7). Oracle Corporation usually extends PL/SQL functionality with each successive release of the Oracle Database.
PL/SQL includes procedural language elements such as conditions and loops. It allows declaration of constants and variables, procedures and functions, types and variables of those types, and triggers. It can handle exceptions (runtime errors). Arrays are supported involving the use of PL/SQL collections. Implementations from version 8 of Oracle Database onwards have included features associated with object-orientation. One can create PL/SQL units such as procedures, functions, packages, types, and triggers, which are stored in the database for reuse by applications that use any of the Oracle Database programmatic interfaces.
PL/SQL works analogously to the embedded procedural languages associated with other relational databases. For example, Sybase ASE and Microsoft SQL Server have Transact-SQL, PostgreSQL has PL/pgSQL (which emulates PL/SQL to an extent), and IBM DB2 includes SQL Procedural Language, which conforms to the ISO SQL’s SQL/PSM standard.
The designers of PL/SQL modeled its syntax on that of Ada. Both Ada and PL/SQL have Pascal as a common ancestor, and so PL/SQL also resembles Pascal in several aspects. However, the structure of a PL/SQL package does not resemble the basic Object Pascal program structure as implemented by a Borland Delphi or Free Pascal unit. Programmers can define public and private global data-types, constants and static variables in a PL/SQL package.
PL/SQL also allows for the definition of classes and instantiating these as objects in PL/SQL code. This resembles usage in object-oriented programming languages like Object Pascal, C++ and Java. PL/SQL refers to a class as an "Abstract Data Type" (ADT) or "User Defined Type" (UDT), and defines it as an Oracle SQL data-type as opposed to a PL/SQL user-defined type, allowing its use in both the Oracle SQL Engine and the Oracle PL/SQL engine. The constructor and methods of an Abstract Data Type are written in PL/SQL. The resulting Abstract Data Type can operate as an object class in PL/SQL. Such objects can also persist as column values in Oracle database tables.
PL/SQL is fundamentally distinct from Transact-SQL, despite superficial similarities. Porting code from one to the other usually involves non-trivial work, not only due to the differences in the feature sets of the two languages, but also due to the very significant differences in the way Oracle and SQL Server deal with concurrency and locking. There are software tools available that claim to facilitate porting including Oracle Translation Scratch Editor, CEITON MSSQL/Oracle Compiler  and SwisSQL.
The StepSqlite product is a PL/SQL compiler for the popular small database SQLite.
PL/SQL Program Unit
A PL/SQL program unit is one of the following: PL/SQL anonymous block, procedure, function, package specification, package body, trigger, type specification, type body, library. Program units are the PL/SQL source code that is compiled, developed and ultimately executed on the database.
The basic unit of a PL/SQL source program is the block, which groups together related declarations and statements. A PL/SQL block is defined by the keywords DECLARE, BEGIN, EXCEPTION, and END. These keywords divide the block into a declarative part, an executable part, and an exception-handling part. The declaration section is optional and may be used to define and initialize constants and variables. If a variable is not initialized then it defaults to NULL value. The optional exception-handling part is used to handle run time errors. Only the executable part is required. A block can have a label.
Packages are groups of conceptually linked functions, procedures, variables, PL/SQL table and record TYPE statements, constants, cursors etc. The use of packages promotes re-use of code. Packages are composed of the package specification and an optional package body. The specification is the interface to the application; it declares the types, variables, constants, exceptions, cursors, and subprograms available. The body fully defines cursors and subprograms, and so implements the specification. Two advantages of packages are:
Modular approach, encapsulation/hiding of business logic, security, performance improvement, re-usability. They support object-oriented programming features like function overloading and encapsulation.
Using package variables one can declare session level (scoped) variables, since variables declared in the package specification have a session scope.
More Details :-
Delete command first check the where condition , get the satisfied tuple..check the triggers .. and then Copy it in the Roll-back table Space (Eqivalent to recyclebin ) and then . delete the rows ..
truncate directly delete the data..
That is why Delete is slower then truncate..
Also Delete is a DML Command so it can be roll-backed because [ Transaction Control (TCL): statements are used to manage the changes made by DML statements ]
truncate and drop are DDL commands , cannot use TCL commands on them .
We can use flashback table statement to retrieve the content back..from recyclebin table
In a shop: - Give me a roll of toilet paper. - What color would you like? - White please, I will color it myself… - Hi, John! I have heard that you died three times already! - Hmm, but you’re no better – you haven’t come to any of my funerals. Could you fax over a copy? No, I can‘t fax because of where I live. Where do you live? The 21st century. Get a life - I’ve heard they’re cheap now on eBay Thanks to Blaine Zernechel.
April fool’s day If there are hopeless fools, then there should also be fools, which give hope.
As experience shows, its easier to fool somebody on a regular day, rather than on April 1st.
Question: can a joke, played on April 1st, become a present for the New Year? Answer: yes, as theres exactly 9 months period.
Valentines Day The best thing of being my own date for Valentines Day is knowing Im guaranteed to score.
Christmas gift Dear Santa, Please do not leave my gift under the Christmas tree. Drive it straight into the garage.
Christmas tree - I left my girlfriend a Christmas gift under the Christmas tree. - Is she happy? -Not yet, still looking for it. The forest is large, lots of trees.
Funny relationship jokes - wonderful wife Single guys often dream of having a wise, beautiful and caring wife. But married guys think about it even more often.
Adult jokes - in a bus Conversation in a bus: - You know, yesterday in a bus your wife told me such a great joke that I almost fell out of the bed.
Profession jokes - executioner An interview with an executioner: - So, how long have you been working in this job? - Well, around 10 years… - And how are you doing there? - Well. no one complained so far.
Daily life jokes - Boy, do you pray before you eat? - No, why should I - my mom is a good cook.
Jokes about dating - magazine The announcement in a magazine: in the next issue we will be writing about to make your boyfriend a little nervous with the help of a marker and a pregnancy test. Daily life situations - in the cafe - Waiter, there’s a bee in my soup! - Yes sir, the fly has a day-off
Profession joke - A priest A priest tells the prayers: - We have one good news and one – bad ones. The good thing is that we have money for the repair of the church. The bad one – the money are still in your pockets.