Why do I get PLS-00302: component must be declared when it exists?

Question

I am using Oracle 10.2. I am working in some scripts to move some ORACLE Objects from one SCHEMA (S1) to another (S2). I am creating the functions with DBA role. When moved, one of my functions becomes invalid, but I don't understand why. Its code goes along these lines: MY_FUNC ``` CREATE OR REPLACE FUNCTION S2."MY_FUNC" RETURN VARCHAR2 IS something VARCHAR2; othervar VARCHAR2 (50):= 'TEST'; BEGIN something := S2.MY_FUNC2(); /*some code*/ return othervar; END; / ``` If I use `MY_FUNC2` without the schema, It works: `something := MY_FUNC2();` instead of `something := S2.MY_FUNC2();` My_FUNC2 ``` CREATE OR REPLACE FUNCTION S2."MY_FUNC2" RETURN VARCHAR2 IS something BOOLEAN; othervar VARCHAR2 (50) := 'TEST2'; BEGIN /*some code*/ return othervar; END; / ``` MY_FUNC2 has a synonym like this: ``` CREATE OR REPLACE PUBLIC SYNONYM "MY_FUNC2" FOR "S2"."MY_FUNC2" ``` `MY_FUNC` compiles with errors: PLS-00302: component 'MY_FUNC2' must be declared I don't understand why I am getting this error,…

Accepted Answer

You can get that error if you have an object with the same name as the schema. For example:

```
create sequence s2;

begin
  s2.a;
end;
/

ORA-06550: line 2, column 6:
PLS-00302: component 'A' must be declared
ORA-06550: line 2, column 3:
PL/SQL: Statement ignored
```

When you refer to `S2.MY_FUNC2` the object name is being resolved so it doesn't try to evaluate S2 as a schema name. When you just call it as `MY_FUNC2` there is no confusion, so it works.

The documentation explains name resolution. The first piece of the qualified object name - S2 here - is evaluated as an object on the current schema before it is evaluated as a different schema.

It might not be a sequence; other objects can cause the same error. You can check for the existence of objects with the same name by querying the data dictionary.

```
select owner, object_type, object_name
from all_objects
where object_name = 'S2';
```

Why do I get PLS-00302: component must be declared when it exists?

Solution

Problem