HTML

Home
Basics Elements and Attributes Headings and Paragraphs Styles and Colors Class and ID Attribute Quotation and Formating Elements Forms Tasks
Introduction CSS Types pseudo class Table with Styles Overflow Properties Display Properties Position Property Line-Height&Letter-Spacing Periodic Table
Introduction Display Properties Identifiers Operators String Methods Array Functions Object Event Handling Dialog Boxes Calculator Design
Introduction Basic Sql Alter and Tables Constraints Insert and Select Operators Joins Group by&Union Backup Exception Handling Views&User Defined Functions Company Database
Introduction Variables & Operators Conditional & Looping Statements Functions & String Expressions Pointers & Recursion Array & Files Patterns
Introduction
Configuration Introduction Sql
MasterDev
1.Exception Handling:
An exception is an error condition during a program execution.
By using exception block we can such type of errors.
There are two types of exceptions
   1.System defined Exception
   2.User defined Exception
Syntax:
   Declare
    //Declaration Section
   Begin Try
    //Executable Commands;
   End Try
   Began Catch
    //When exception_1 then
     Statement
    //When exception_2 then
     Statement
   End Catch;
 i. System defined Exception:
  These exceptions are predefined in sql which get raised when certain database rule is violated.
Code:
Output:
ii.User defined Exception:
  The type of exceptions that are generated by the user not by the system based on the           code.
Code:
Output:
2.Began and End:
It is mandatory section
It consists of the executable statements.
It should have at least one executable line of code.
Syntax:
Begin
Executable statements
End
3.Commit and Rollback:
Commit is used for the permanent changes.
When we use Commit in any query then the change made by that query will be permanent.
We can't rollback after commit.
Syntax:
Begin Transaction Transaction_Name
Statement
Commit Transaction Transaction_Name
i.Command:

Output:
ii.Rollback
Rollback is used to undo the changes made by any command.
But only before a commit command is done.
We can't rollback the data which has been committed in the database.
Syntax:
Begin Transaction Transaction_Name
Statement
Rollback Transaction Transaction_Name
4.Print:
Print is nothing but a return statement.
It is used to return messages to the client.
It is used for troubleshooting the code by displaying the message or variables.
Command:
Output:
Command:
Output:
5.Variables:
A variables is nothing but a name given to a storage area.
Variables must be declared in the declaration section.
variables names are valid identifier in sql.
There are two types of variables.
1.Local variable:Variable declared in inner block and not accessible to outer block.\
2.Global variable:Variable declared in the outermost block.
  Command:
Output:

6.If else:
If else statement is used to execute when a condition is true,or executes a different code if the condition evaluates to false.
Syntax:
If condition
{ statements to execute when the condition is true}
else
{ statements to execute when the condition is false}
Command:
Output:

7.While:
If the expression is true, the statement is executed continuously until the expression is false.
It again determines whether to execute the statement or not.
Syntax:
while (expression)
sql_statement;
[break]
sql_statement;
[continue]
Break: Break forces a loop to exit immediately.
If we want to stop a loop in any intermediate position then we can use break keyword.
Continue:
It is opposite of Break.
Instead of stopping the loop, It immediately loops again.It skips the rest of the code.
Command: For Break
Output:
Command: For Continue

Output:

8.Return:
Return values can be used with in the stored procedures.
It is immediate and complete and can be used at any point to exit from a procedure.
Statements that follow return are not executed.


Subscribe to: Posts (Atom)