Why a type cannot be constrained? - sql

Question

I am struggling with the following code:
DECLARE
TOTACID TAB_OF_ID(50);
RES NUMBER;
BEGIN
SELECT DISTINCT ID INTO TOTACID
FROM TABLE_B;
FOR indx IN 1 .. TOTACID.COUNT
LOOP
RES := F_IMPORT(TOTACID(indx));
DBMS_OUTPUT.PUT_LINE ('Moved ID ' || RES);
END LOOP;
END;
/
When I run it, it fails with the error:
Error report -
ORA-06550: line 2, column 11:
PLS-00566: type name "TAB_OF_ID" cannot be constrained
ORA-06550: line 5, column 19:
PL/SQL: ORA-00932: inconsistent datatypes: expected UDT got NUMBER
ORA-06550: line 5, column 3:
PL/SQL: SQL Statement ignored
06550. 00000 - "line %s, column %s:\n%s"
*Cause: Usually a PL/SQL compilation error.
*Action:
Where TAB_OF_ID has been declared as follows:
create or replace TYPE TAB_OF_ID AS table of NUMBER(19,2);
I don't understand what is wrong. It seems that I cannot declare TOTACID TAB_OF_ID(50) but in a function I created some days ago I could declare LIS_ID TAB_OF_ID := TAB_OF_ID(50); and it works properly.
What is the difference with the script I have here?

Answer 1

Obviously TOTACID TAB_OF_ID(50) is different to LIS_ID TAB_OF_ID := TAB_OF_ID(50); The command is like
{variable name} {data type} := {inital value};
where := {inital value} is optional.
TOTACID TAB_OF_ID(50) would mean
{variable name} {inital value};
which is not valid syntax.

Answer 2

You can not declare the variable by assigning your table a fixed number of records, so you need something like:
DECLARE
TOTACID TAB_OF_ID;
RES NUMBER;
BEGIN
SELECT DISTINCT ID bulk collect INTO TOTACID
FROM TABLE_B;
...
END;
/
Also, notice that you are fetching more than one value, so you need BULK COLLECT INTO.
About
LIS_ID TAB_OF_ID := TAB_OF_ID(50);
here you are not declaring a variable with a given number of records, but you are assigning to a variable the 50th value of the table.