Summary of Predefined PL/SQL Exceptions#
An internal exception is raised automatically if your PL/SQL program violates an Oracle rule or exceeds a system-dependent limit. PL/SQL predefines some common Oracle errors as exceptions. For example, PL/SQL raises the predefined exception NO_DATA_FOUND if a SELECT INTO statement returns no rows.
PL/SQL declares predefined exceptions globally in package STANDARD. You need not declare them yourself. You can write handlers for predefined exceptions using the names in the following table:
| Exception | Raise When ... |
|---|---|
| ACCESS_INTO_NULL | A program attempts to assign values to the attributes of an uninitialized object |
| CASE_NOT_FOUND | None of the choices in the WHEN clauses of a CASE statement is selected, and there is no ELSE clause. |
| COLLECTION_IS_NULL | A program attempts to apply collection methods other than EXISTS to an uninitialized nested table or varray, or the program attempts to assign values to the elements of an uninitialized nested table or varray. |
| CURSOR_ALREADY_OPEN | A program attempts to open an already open cursor. A cursor must be closed before it can be reopened. A cursor FOR loop automatically opens the cursor to which it refers, so your program cannot open that cursor inside the loop. |
| DUP_VAL_ON_INDEX | A program attempts to store duplicate values in a column that is constrained by a unique index. |
| INVALID_CURSOR | A program attempts a cursor operation that is not allowed, such as closing an unopened cursor. |
| INVALID_NUMBER | n a SQL statement, the conversion of a character string into a number fails because the string does not represent a valid number. (In procedural statements, VALUE_ERROR is raised.) This exception is also raised when the LIMIT-clause expression in a bulk FETCH statement does not evaluate to a positive number. |
| LOGIN_DENIED | A program attempts to log on to Oracle with an invalid username or password. |
| NO_DATA_FOUND | A SELECT INTO statement returns no rows, or your program references a deleted element in a nested table or an uninitialized element in an index-by table. Because this exception is used internally by some SQL functions to signal completion, you should not rely on this exception being propagated if you raise it within a function that is called as part of a query. |
| NOT_LOGGED_ON | A program issues a database call without being connected to Oracle. |
| PROGRAM_ERROR | PL/SQL has an internal problem. |
| ROWTYPE_MISMATCH | The host cursor variable and PL/SQL cursor variable involved in an assignment have incompatible return types. When an open host cursor variable is passed to a stored subprogram, the return types of the actual and formal parameters must be compatible. |
| SELF_IS_NULL | A program attempts to call a MEMBER method, but the instance of the object type has not been initialized. The built-in parameter SELF points to the object, and is always the first parameter passed to a MEMBER method. |
| STORAGE_ERROR | PL/SQL runs out of memory or memory has been corrupted. |
| SUBSCRIPT_BEYOND_COUNT | A program references a nested table or varray element using an index number larger than the number of elements in the collection. |
| SUBSCRIPT_OUTSIDE_LIMIT | A program references a nested table or varray element using an index number (-1 for example) that is outside the legal range. |
| SYS_INVALID_ROWID | The conversion of a character string into a universal rowid fails because the character string does not represent a valid rowid. |
| TIMEOUT_ON_RESOURCE | A time out occurs while Oracle is waiting for a resource. |
| TOO_MANY_ROWS | A SELECT INTO statement returns more than one row. |
| VALUE_ERROR | An arithmetic, conversion, truncation, or size-constraint error occurs. For example, when your program selects a column value into a character variable, if the value is longer than the declared length of the variable, PL/SQL aborts the assignment and raises VALUE_ERROR. In procedural statements, VALUE_ERROR is raised if the conversion of a character string into a number fails. (In SQL statements, INVALID_NUMBER is raised.) |
| ZERO_DIVIDE | A program attempts to divide a number by zero. |
DECLARE
-- variables and cursors go here
BEGIN
-- PL/SQL logic goes here
EXCEPTION -- exception handlers begin
-- Only one of the WHEN blocks is executed.
WHEN ZERO_DIVIDE THEN -- handles 'division by zero' error
-- statement 1;
-- statement 2;
-- etc
WHEN OTHERS THEN -- handles all other errors
-- statement 1;
-- statement 2;
-- etc
END;
