PL Oracle Database / SQL using the (four)

First, the basic usage

1. PL / SQL process data display (output)
   set serveroutput on; - a display output
   set serveroutput on; - Close output
   dbms_output.put_line (); - Client output
2. Assignment of variables and constants
   keyword default;
   assignment statement: =;
   using statement SELECT ····· INTO ·······
   variable Connectors: ||;
   accepting user input: variable name: = '& variables name';
3. Properties Type
   % TYPE: reference variable and the data type of a database column;
   % ROWTYPE: providing record type represented by row in a table;
   use attribute type advantages: does not need to know the specific type of the referenced table columns.

Second, the control structure

1. Conditions control
   -IF statement
   
   -CASE statement
   
2. Circulation control
   -LOOP loop
   
   -WHILE cycle
   
   -FOR cycle
   
3. Sequence control
   -GOTO statement
   
   -NULL statement

Third, dynamic SQL

1. Execute dynamic SQL syntax
   
   example:
   

2. Dynamic SQL statements executed with parameters
   
   Example:
   

Fourth, exception handling

1. Exception type
   a, the predefined exception - Implicit initiated when the PL / SQL program violates Oracle rule or exceed the system limit;
   B, a user-defined exception - the user may define an exception in PL / declaration section SQL blocks, custom exception by RAISE statement to explicitly throw.

2. Predefined exception handling
   
   
   

3. Custom exception handling
   
   

4. Non-predefined exceptions