Oracle Error PLS-00306

Error code

PLS-00306

Product

Oracle Database

Versions

Oracle Database 19c, 21c, 23ai and 26ai (same wording)

Category

PL/SQL & Triggers

Last reviewed

24 October 2026

What it means

PLS-00306 means a call to a procedure or function does not match any declaration of it: there are too many or too few arguments, an argument has an incompatible type, or no overloaded version fits.

When the PL/SQL compiler meets a call, it looks for a declaration with that name, first in the current scope and then in enclosing scopes, and checks that the parameter lists match: every required formal parameter (one without a default) must have an actual argument, and each argument must be of a compatible type. If no declaration matches, it reports PLS-00306 with the subprogram name. Oracle's action is to check the spelling and declaration of the subprogram, that the call is correct, that the parameters are of the right data type, and that the declaration is placed correctly in the block structure.

The message names the subprogram but not which argument is wrong, so compare the call with the declaration argument by argument. For a stored procedure, ALL_ARGUMENTS lists the declared parameters (one set per overload). Calls from applications through a driver are compiled as small anonymous blocks, so a wrong number of bind parameters there produces the same error under ORA-06550.

Common causes

• A required parameter is missing, or an extra argument is passed, often after the procedure's parameter list was changed and callers were not.
• An argument has an incompatible type: a record, collection or object where a scalar is expected, or the other way round, or a value of a different user-defined type with the same shape.
• The subprogram is overloaded and the argument types match none of the versions, as in Oracle's SWAP example, where a nested procedure of the same name hides the one meant.
• Named notation uses a parameter name the subprogram does not have, so the call cannot be matched to its parameter list.
• An application calls a stored procedure with a different number of bind parameters from its declaration.

Diagnose it

Read-only These queries only read the data dictionary (USER_, ALL_ and DBA_ views) and dynamic performance views (V$). They do not change data, privileges or settings, so they are safe to run first. DBA_ and V$ views need the matching privileges.

SELECT overload, position, argument_name, data_type, in_out, defaulted,
       type_owner, type_name
FROM all_arguments
WHERE owner = 'SHOP'
  AND object_name = 'ADD_CUSTOMER'
  AND package_name IS NULL   -- or = 'CUSTOMER_API' for a package
ORDER BY overload, sequence;

SELECT object_name, object_type, status, last_ddl_time
FROM all_objects
WHERE owner = 'SHOP'
  AND object_name IN ('ADD_CUSTOMER', 'CUSTOMER_API')
ORDER BY object_type;

SELECT owner, name, type
FROM all_dependencies
WHERE referenced_owner = 'SHOP'
  AND referenced_name = 'ADD_CUSTOMER'
ORDER BY owner, name;

How to fix it

Each fix is labelled with what it changes. Try read-only checks and the least invasive fix first, and test changes outside production.

CREATE OR REPLACE PROCEDURE shop.register_web_user (p_name IN VARCHAR2, p_email IN VARCHAR2)
IS
BEGIN
  shop.add_customer(p_name  => p_name,
                    p_email => LOWER(TRIM(p_email)));
END;
/

CREATE OR REPLACE PROCEDURE shop.add_customer (
  p_name      IN VARCHAR2,
  p_email     IN VARCHAR2,
  p_marketing IN VARCHAR2 DEFAULT 'N')   -- new, optional
IS
BEGIN
  INSERT INTO shop.customers (full_name, email, marketing_opt_in)
  VALUES (p_name, p_email, p_marketing);
END;
/

Examples

A required parameter is missing

Not reproduced here: no Oracle Database is installed for this site. The layout follows the PLS-00306 example in Oracle's PL/SQL Language Reference (subprogram invocation resolution); names and positions are illustrative.

CREATE OR REPLACE PROCEDURE add_customer (p_name IN VARCHAR2, p_email IN VARCHAR2) IS
BEGIN
  INSERT INTO customers (full_name, email) VALUES (p_name, p_email);
END;
/

BEGIN
  add_customer('Sara Ahmed');   -- p_email has no default
END;
/

ORA-06550: line 2, column 3:
PLS-00306: wrong number or types of arguments in call to 'ADD_CUSTOMER'
ORA-06550: line 2, column 3:
PL/SQL: Statement ignored

A record passed where a number is expected

Not reproduced here: no Oracle Database is installed for this site. The message is from Oracle's error reference and the layout from its documented example; names and positions are illustrative. The message names only the subprogram, so compare the argument with ALL_ARGUMENTS to see that it expects a NUMBER.

-- shop.order_api.ship(p_order_id IN NUMBER)
DECLARE
  r orders%ROWTYPE;
BEGIN
  SELECT * INTO r FROM orders WHERE id = 1001;
  shop.order_api.ship(r);   -- should be r.id
END;
/

ORA-06550: line 6, column 3:
PLS-00306: wrong number or types of arguments in call to 'SHIP'
ORA-06550: line 6, column 3:
PL/SQL: Statement ignored

How to prevent it

Use named notation for calls with more than one or two parameters, give new parameters defaults, and check ALL_DEPENDENCIES for callers before changing a signature. Keep public signatures in package specifications stable and add overloads deliberately.

Recompile dependent code and check USER_ERRORS in every deployment, so a mismatched call fails at deploy time rather than when a user first runs it.

Common questions

Learn more on CodeWithSQL

• Stored procedures and functions
• Advanced stored procedures

Official documentation

• PLS-00306 (Oracle Database Error Messages)
• Subprogram invocation resolution (Oracle PL/SQL Language Reference 19c)
• Subprogram parameters, notation and defaults (Oracle PL/SQL Language Reference 19c)
• ALL_ARGUMENTS (Oracle Database Reference 19c)

Last technically reviewed 24 October 2026; examples and diagnostics run on Oracle Database Error Messages reference (26ai, 21c and 19c); not run locally. Messages and explanations follow Oracle's Database Error Messages reference; no Oracle Database was available, so the examples were not run locally.