How to use an Oracle Associative Array in a SQL query

Question

ODP.Net exposes the ability to pass Associative Arrays as params into an Oracle stored procedure from C#. Its a nice feature unless you are trying to use the data contained

Answer 1

I would create a database type like this:

create type v2t as table of varchar2(30);
/

And then in the procedure:

FOR i IN 1..associativeArray.COUNT LOOP
    databaseArray.extend(1);
    databaseArray(i) := associativeArray(i);
END LOOP;

OPEN refCursor FOR
SELECT T.*
FROM   SOME_TABLE T,
       ( SELECT COLUMN_VALUE V
         FROM   TABLE( databaseArray )
       ) T2
WHERE  T.NAME = T2.V;

(where databaseArray is declared to be of type v2t.)

Answer 2

You cannot use associative arrays in the SQL scope - they are only usable in the PL/SQL scope.

One method is to map the associative array to a collection (which can be used in the SQL scope if the collection type has been defined in the SQL scope and not the PL/SQL scope).

SQL:

CREATE TYPE VARCHAR2_200_Array_Type AS TABLE OF VARCHAR2(200);
/

PL/SQL

DECLARE
  TYPE associativeArrayType IS TABLE OF VARCHAR2(200) INDEX BY PLS_INTEGER;
  i                PLS_INTEGER;
  associativeArray associativeArrayType;
  array            VARCHAR2_200_Array_Type;
  cur              SYS_REFCURSOR;
BEGIN
  -- Sample data in the (sparse) associative array
  associativeArray(-2) := 'Test 1';
  associativeArray(0)  := 'Test 2';
  associativeArray(7)  := 'Test 3';

  -- Initialise the collection
  array := VARCHAR2_200_Array_Type();

  -- Loop through the associative array
  i := associativeArray.FIRST;
  WHILE i IS NOT NULL LOOP
    array.EXTEND(1);
    array(array.COUNT) := associativeArray(i);
    i := associativeArray.NEXT(i);
  END LOOP;

  -- Use the collection in a query
  OPEN cur FOR
    SELECT *
    FROM   your_table
    WHERE  your_column MEMBER OF array;
END;
/