How does Oracle declare identifiers?

2 years ago
Ava Mitchell
2 minutes

In Oracle, identifiers can be declared using the following methods:

  1. Variable declaration: Use the keyword DECLARE to declare one or more variables, and then use the keyword VAR (optional) to specify the variable’s name and data type.
  2. For example:
    DECLARE
    var_name datatype;
    …
    VAR var_name datatype;
  3. Constant declaration: Use the keyword CONSTANT to declare a constant, then use the keyword TYPE to specify the data type of the constant.
  4. For example:
    DECLARE a constant named const_name of type TYPE with a value of value;
  5. Cursor declaration: Use the keyword CURSOR to declare a cursor, then use the keyword FOR SELECT to specify the cursor’s query statement.
  6. For instance:
    CREATE a cursor named cursor_name that SELECTS column1, column2, … FROM table_name WHERE condition;
  7. Exception declaration: Use the keyword EXCEPTION to declare an exception.
  8. For example:
    DECLARE exception_name EXCEPTION;
  9. Declare a subroutine (procedure or function): Use the keywords PROCEDURE or FUNCTION to declare a subroutine, then specify the name, parameter list, and return type of the subroutine.
  10. For example:
    In the PROCEDURE procedure_name, parameters param1 and param2 are declared with their respective datatypes.
    In the FUNCTION function_name, parameters param1 and param2 are specified with their datatypes and the return type is declared.

It is important to note that when declaring identifiers, you need to specify the identifier’s name and data type (if applicable), and follow Oracle’s naming conventions and data type requirements.

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