This is a translation reference to convert the Oracle Associative Array Declaration to Snowflake
This section is a work in progress, information may change in the future.
Some parts in the output code are omitted for clarity reasons.
Description
An associative array (formerly called PL/SQL table or index-by table) is a set of key-value pairs. Each key is a unique index, used to locate the associated value with the syntax variable_name(index).
The data type of index can be either a string type (VARCHAR2, VARCHAR, STRING, or LONG) or PLS_INTEGER. Indexes are stored in sort order, not creation order. For string types, sort order is determined by the initialization parameters NLS_SORT and NLS_COMP.
For the translation, the type definition is replaced by an OBJECT Semi-structured Data Type and then its usages are changed accordingly across any operations.
In order to define an Associative Array type, the syntax is as follows:
type_definition := TYPE IS TABLE OF datatype INDEX BY indexing_datatype;
indexing_datatype := { PLS_INTEGER
| BINARY_INTEGER
| string_datatype
}
To declare a variable of this type:
variable_name collection_type;
Sample Source Patterns
Varchar-indexed Associative Array
Oracle
CREATE OR REPLACE PROCEDURE associative_array
IS
TYPE associate_array_typ IS TABLE OF INTEGER
INDEX BY VARCHAR2(50);
associate_array associate_array_typ := associate_array_typ();
associate_index VARCHAR2(50);
BEGIN
associate_array('abc') := 1;
associate_array('bca') := 2;
associate_array('def') := 3;
DBMS_OUTPUT.PUT_LINE(associate_array('abc'));
associate_array('abc') := 4;
--THROWS 'NO DATA FOUND'
--DBMS_OUTPUT.PUT_LINE(associate_array('no exists'));
DBMS_OUTPUT.PUT_LINE(associate_array.COUNT);
associate_index := associate_array.FIRST;
WHILE associate_index IS NOT NULL
LOOP
DBMS_OUTPUT.PUT_LINE(associate_array(associate_index));
associate_index := associate_array.NEXT(associate_index);
END LOOP;
END;
CALL associative_array();
DBMS OUTPUT
-----------
1
3
4
2
3
Snowflake
Please note the 'true' parameter in the OBJECT_INSERT. This is so that the element is updated if it is already present in the array.
CREATE OR REPLACE PROCEDURE PUBLIC.associative_array ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
DECLARE
associate_array OBJECT := OBJECT_CONSTRUCT();
associate_index VARCHAR(50);
BEGIN
associate_array := OBJECT_INSERT(associate_array, 'abc', 1, true);
associate_array := OBJECT_INSERT(associate_array, 'bca', 2, true);
associate_array := OBJECT_INSERT(associate_array, 'def', 3, true);
CALL DBMS_OUTPUT.PUT_LINE(:associate_array['abc']);
CALL DBMS_OUTPUT.PUT_LINE(:associate_array['not found']);
associate_array := OBJECT_INSERT(:associate_array, 'abc', 4, true);
CALL DBMS_OUTPUT.PUT_LINE(ARRAY_SIZE(OBJECT_KEYS(:associate_array)));
FOR i IN 1 TO ARRAY_SIZE(OBJECT_KEYS(:associate_array))
LOOP
associate_index := OBJECT_KEYS(:associate_array)[:i-1];
CALL DBMS_OUTPUT.PUT_LINE(:associate_array[:associate_index]);
END LOOP;
END;
$$;
CALL PUBLIC.associative_array();
SELECT * FROM DBMS_OUTPUT.DBMS_OUTPUT_LOG;
DBMS OUTPUT
-----------
1
3
4
2
3
Numeric-indexed Associative Array
Oracle
CREATE OR REPLACE PROCEDURE numeric_associative_array
IS
TYPE numeric_associative_array_typ IS TABLE OF INTEGER
INDEX BY PLS_INTEGER;
associate_array numeric_associativ
e_array_typ := numeric_associative_array_typ();
associate_index PLS_INTEGER;
BEGIN
associate_array(1) := -1;
associate_array(2) := -2;
associate_array(3) := -3;
DBMS_OUTPUT.PUT_LINE(associate_array(1));
associate_array(1) := -4;
DBMS_OUTPUT.PUT_LINE(associate_array.COUNT);
associate_index := associate_array.FIRST;
WHILE associate_index IS NOT NULL
LOOP
DBMS_OUTPUT.PUT_LINE(associate_array(associate_index));
associate_index := associate_array.NEXT(associate_index);
END LOOP;
END;
CALL numeric_associative_array();
DBMS OUTPUT
-----------
-1
3
-4
-2
-3
Snowflake
Please note that the numeric value is converted to varchar accordingly when the operation needs it. Additionally, note the 'true' parameter in the OBJECT_INSERT. This is so that the element is updated if it is already present in the array.
CREATE OR REPLACE PROCEDURE PUBLIC.numeric_associative_array ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
DECLARE
associate_array OBJECT := OBJECT_CONSTRUCT();
associate_index NUMBER;
BEGIN
associate_array := OBJECT_INSERT(associate_array, '1', -1, true);
associate_array := OBJECT_INSERT(associate_array, '2', -2, true);
associate_array := OBJECT_INSERT(associate_array, '3', -3, true);
CALL DBMS_OUTPUT.PUT_LINE(:associate_array['1']);
associate_array := OBJECT_INSERT(:associate_array, '1', -4, true);
CALL DBMS_OUTPUT.PUT_LINE(ARRAY_SIZE(OBJECT_KEYS(:associate_array)));
FOR i IN 1 TO ARRAY_SIZE(OBJECT_KEYS(:associate_array))
LOOP
associate_index := OBJECT_KEYS(:associate_array)[:i-1];
CALL DBMS_OUTPUT.PUT_LINE(:associate_array[:associate_index::VARCHAR]);
END LOOP;
END;
$$;
CALL PUBLIC.numeric_associative_array();
SELECT * FROM DBMS_OUTPUT.DBMS_OUTPUT_LOG;
DBMS OUTPUT
-----------
-1
3
-4
-2
-3
Record-element Numeric-indexed Associative Array
In this case, the associative array is composed of a Record-structure, and this structure needs to be preserved. For this purpose, further operations on insertions were added.
Oracle
CREATE OR REPLACE PROCEDURE record_associative_array
IS
TYPE record_typ IS RECORD(col1 INTEGER);
TYPE record_associative_array_typ IS TABLE OF record_typ
INDEX BY PLS_INTEGER;
associate_array record_associati ve_array_typ := record_associative_array_typ();
associate_index PLS_INTEGER;
BEGIN
associate_array(1).col1 := -1;
associate_array(2).col1 := -2;
associate_array(3).col1 := -3;
DBMS_OUTPUT.PUT_LINE(associate_array(1).col1);
associate_array(4).col1 := -4;
DBMS_OUTPUT.PUT_LINE(associate_array.COUNT);
associate_index := associate_array.FIRST;
WHILE associate_index IS NOT NULL
LOOP
DBMS_OUTPUT.PUT_LINE(associate_array(associate_index).col1);
associate_index := associate_array.NEXT(associate_index);
END LOOP;
END;
/
CALL record_associative_array();
DBMS OUTPUT
-----------
-1
3
-4
-2
-3
Snowflake
In this scenario, the insertion/update assumes an automatic creation of the record within the associative array and this needs to be taken into account when creating new records.
CREATE OR REPLACE PROCEDURE PUBLIC.record_associative_array ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
DECLARE
associate_array OBJECT := OBJECT_CONSTRUCT();
associate_index NUMBER;
BEGIN
associate_array := OBJECT_INSERT(associate_array, '1', OBJECT_INSERT(NVL(associate_array['1'], OBJECT_CONSTRUCT()), 'col1', -1, true), true);
associate_array := OBJECT_INSERT(associate_array, '2', OBJECT_INSERT(NVL(associate_array['2'], OBJECT_CONSTRUCT()), 'col1', -2, true), true);
associate_array := OBJECT_INSERT(associate_array, '3', OBJECT_INSERT(NVL(associate_array['3'], OBJECT_CONSTRUCT()), 'col1', -3, true), true);
CALL DBMS_OUTPUT.PUT_LINE(:associate_array['1']:col1);
associate_array := OBJECT_INSERT(associate_array, '1', OBJECT_INSERT(NVL(associate_array['1'], OBJECT_CONSTRUCT()), 'col1', -4, true), true);
CALL DBMS_OUTPUT.PUT_LINE(ARRAY_SIZE(OBJECT_KEYS(:associate_array)));
FOR i IN 1 TO ARRAY_SIZE(OBJECT_KEYS(:associate_array))
LOOP
associate_index := OBJECT_KEYS(:associate_array)[:i-1];
CALL DBMS_OUTPUT.PUT_LINE(:associate_array[:associate_index::VARCHAR]:col1);
END LOOP;
END;
$$;
CALL PUBLIC.record_associative_array();
SELECT * FROM DBMS_OUTPUT.DBMS_OUTPUT_LOG;
DBMS OUTPUT
-----------
-1
3
-4
-2
-3
Known Issues
1. They are currently not being recognized
SnowConvert treats these collections as Nested Table Arrays. There is a work item to fix this.
