I have the following code which works just fine in building a 2D array indexed by VARCHAR2. But I have a question about how I would instantiate the top-level array with an "empty" second level array. (See the comments in the code.)
The only way I've found to instantiate the initial array (inside the Add() procedure) is to declare a dummy variable (which is itself an empty array), and assign it to the top-level array:
DECLARE
TYPE pt_array IS TABLE OF number INDEX BY VARCHAR2(25);
TYPE prj_array IS TABLE OF pt_array INDEX BY VARCHAR2(25);
pt_array_ pt_array;
pj_array_ prj_array;
PROCEDURE Add (
act_ IN VARCHAR2,
pt_ IN VARCHAR2,
val_ IN NUMBER )
IS
dummy_empty_array pt_array; -- initiate a dummy variable
BEGIN
IF not pj_array_.EXISTS(act_) THEN
pj_array_(act_) := dummy_empty_array; -- can I initiate here without having to declare a variable?
END IF;
IF not pj_array_(act_).EXISTS(pt_) THEN
pj_array_(act_)(pt_) := val_;
END IF;
END Add;
BEGIN
Add ('A', '123', 1);
Add ('A', '456', 1);
Add ('B', '456', 1);
END;
Most languages offer the ability to assign an anonymous array when required (i.e. without having to define an intermittent variable). For example, in Javascript you'd just do x = [];. But I haven't found a way to do this in PL/SQL.
I've tried various different syntaxes, one obvious example being the following (which errors at compile time with "no function with name 'PT_ARRAY' exists"):
pj_array_(act_) := pt_array();
Also, the concept of using keyword EXTEND doesn't apply if you're declaring you array/tables with an INDEX BY clause.
So my question is whether it's possible to write this code (i.e. to initiate the empty array) without the dummy variable?
Related
I have seen questions with this error, but either are calling external stores or trying with incompatible types or using a varray. So i setup a very simple example and still i can not make it work.
DECLARE
TYPE mytype IS TABLE OF VARCHAR2(4) INDEX BY PLS_INTEGER;
mytable mytype;
BEGIN
mytable((mytable.COUNT+1)) := 'COD1';
mytable((mytable.COUNT+1)) := 'COD2';
mytable((mytable.COUNT+1)) := 'COD3';
mytable((mytable.COUNT+1)) := 'COD4';
--IF 'COD1' MEMBER OF mytable THEN DBMS_OUTPUT.PUT_LINE('We have the code'); END IF;
FOR i IN 1..mytable.COUNT LOOP
DBMS_OUTPUT.PUT_LINE(mytable(i));
END LOOP;
END;
I get this if i run it:
COD1
COD2
COD3
COD4
If i uncomment the IF (what i intend to use) i get this error.
PLS-00306: wrong number or types of arguments in call to MEMBER OF
Perhaps I am not using it correctly or something is wrong.
I am trying to use that on a loop, I save the codes that I have used in the "array" then given one code I need to know if it was already used.
My initial solution was to append to a string like ".COD1..COD2." and do a simple INSTR but does not seem right and I like arrays.
I heard of that function (member of) which does what I wanted if only work as I believe it should.
can you tell me How to use correctly, what i am doing wrong or how to solve my problem in a better way?
Almost there...
I change it to
-- Declare
TYPE mytype IS TABLE OF VARCHAR2(4) INDEX BY VARCHAR(4);
mytable mytype;
-- Fill
mytable('COD1') := 'COD1'; -- kind of redundant I only need the index
-- The magic
IF mytable.EXISTS('COD1')...
But I still feel that there should be a better way.
I have tried to illustrate how you can make use of MEMBER function with NESTED TABLE TYPE. It cannot be used with Asociative arrays. Hope it helps.
SET serveroutput ON;
DECLARE
type my_tab
IS
TABLE OF VARCHAR2(100);
tab my_tab;
BEGIN
tab:=my_tab('AVRAJIT','SHUBHOJIT');
IF 'AVRAJIT' member OF (tab) THEN
dbms_output.put_line('Yes');
ELSE
dbms_output.put_line('No');
END IF;
END;
MEMBER OF can only be used with nested tables. You're trying to use it on an associative array. Here is a nice explanation of the differences.
I am new to plsql. I am trying to put two scripts under the same package. These scripts deal with arrays. How do I pass an array into the procedure? If I am to declare the array, do I do it in the specification or the body? I am trying this right now but it doesn't work.
CREATE PACKAGE cop_cow_script AS
PROCEDURE COP_COW_DATALOAD_V2(arr_claims VARRAY(15000) OF VARCHAR2(10), arr_sql VARRAY(500) OF VARCHAR2(1000));
END cop_cow_script;
As you see I want to pass in those two arrays.
You need to declare types in the package specification and use them as parameter types in the procedure declaration:
CREATE OR REPLACE PACKAGE cop_cow_script AS
TYPE arr_claims_t IS VARRAY(15000) OF VARCHAR2(10);
TYPE arr_sql_t IS VARRAY(500) OF VARCHAR2(1000);
PROCEDURE COP_COW_DATALOAD_V2(arr_claims arr_claims_t, arr_sql arr_sql_t);
END cop_cow_script;
/
EDIT - below is an example of the package body - the procedure loops through elements of it's first parameter and prints them using DBMS_OUTPUT.PUT_LINE
PROCEDURE COP_COW_DATALOAD_V2(arr_claims arr_claims_t, arr_sql arr_sql_t)
IS
BEGIN
FOR i IN arr_claims.FIRST .. arr_claims.LAST
LOOP
DBMS_OUTPUT.PUT_LINE( arr_claims( i ) );
END LOOP;
END;
END cop_cow_script;
/
An then you can initialize them and pass to the procedure invocation for example in this way (this is an anonymous block that declares two variables, initializes them and invokes the procedure passing both parameters to it:
DECLARE
my_array1 cop_cow_script.arr_claims_t := cop_cow_script.arr_claims_t();
my_array2 cop_cow_script.arr_sql_t := cop_cow_script.arr_sql_t();
BEGIN
my_array1.extend;
my_array1( 1 ) := 'string 1';
my_array2.extend;
my_array2( 1 ) := 'string 2';
cop_cow_script.COP_COW_DATALOAD_V2( my_array1, my_array2 );
END;
/
First off, I'm hard-pressed to imagine a situation where you'd actually want to use a PL/SQL varray rather than a nested table or an associative array. There really isn't a benefit to declaring a fixed size collection.
Whatever sort of collection type you want, you'd need to declare the collection type either in the package specification or at the SQL level (depending on the type of collection) separate from the procedure specification
CREATE PACKAGE cop_cow_script AS
TYPE arr_claims IS varray(15000) of varchar(10);
TYPE arr_sql IS varray(500) of varchar(1000);
PROCEDURE COP_COW_DATALOAD_V2(p_claims arr_claims,
p_sql arr_sql);
END cop_cow_script;
I'm trying to print keys of an associative array for the simple logic shown below
declare
type std_marks_arr is table of number(10)
index by BINARY_INTEGER;--
std_marks std_marks_arr;
cursor std_id is select student_code from student_master;
begin
for i in std_id
loop
select sum(marks) into std_marks(i.student_code) from student_marks
where student_code=i.student_code;
end loop;
for i in std_marks.first..std_marks.last
loop
dbms_output.put_line(rpad(std_marks(i).key,10,' ')||rpad(std_marks(i),10,' '));
end loop;
end;`
Its giving an error like
'Invalid reference to variable 'NUMBER' in line where i used key
I Know that it can be done by other means but i have to know how can i print index in this situation.
Your variable std_marks has an associative array type as its type, which has no attribute key (and indeed, has no attributes - it's just an array of values).
In your code, i is the index, which will be a simple number, so you would just use this:
for i in std_marks.first..std_marks.last
loop
dbms_output.put_line(rpad(i,10,
' ')||rpad(std_marks(i),10,' '));
end loop
You have a few other issues in your code, however, that will stop it compiling (e.g. missing semicolon) and running (e.g. unless your student codes form a series with no gaps in numeric sequence, your code will raise NO_DATA_FOUND because your loop tries to access all array elements from the First index value to the Last index value, including gaps).
I am having a table Course which have column DepId and Course and some other value. I need to search this table for a some set of (DepId, Course). This set will be decided at runtime.
I want to write a single query in a procedure to fetch all the record pertaining to above set.
For example consider the table has data like
DepId Course ...
------------------
1 A
2 B
3 C
4 D
5 E
6 F
Now only I want to search for below records:
DepId Course ...
------------------
1 A
4 D
What would be most efficient way to write above query?
I was thinking of creating an Array of record and passing it in the 'IN' operator. But I was not able to get any example for this. Can someone guide me on this?
Thanks
Leveraging Oracle Collections to Build Array-typed Solutions
The answer to your question is YES, dimensioned variables such as ARRAYS and COLLECTIONS are viable data types in solving problems where there are multiple values in either or both the input and output values.
Additional good news is that the discussion for a simple example (such as the one in the OP) is pretty much the same as for a complex one. Solutions built with arrays are nicely scalable and dynamic if designed with a little advanced planning.
Some Up Front Design Decisions
There are actual collection types called ARRAYS and ASSOCIATIVE ARRAYS. I chose to use NESTED TABLE TYPES because of their accessibility to direct SQL queries. In some ways, they exhibit "array-like" behavior. There are other trade-offs which can be researched through Oracle references.
The query applied to search the COURSE TABLE would apply a JOIN condition instead of an IN-LIST approach.
The use of a STORED PROCEDURE typed object improves database response. Queries within the procedure call can leverage and reuse already compiled code plus their cached execution plans.
Choosing the Right Collection or Array Type
There are a lot of choices of collection types in Oracle for storing variables into memory. Each has an advantage and some sort of limitation. AskTom from Oracle has a good example and break-down of what a developer can expect by choosing one variable collection type over another.
Using NESTED TABLE Types for Managing Multiple Valued Variables
For this solution, I chose to work with NESTED TABLES because of their ability to be accessed directly through SQL commands. After trying several different approaches, I noticed that the plain-SQL accessibility leads to more clarity in the resulting code.
The down-side is that you will notice that there is a little overhead here and there with respect to declaring an instance of a nested table type, initializing each instance, and managing its size with the addition of new values.
In any case, if you anticipate a unknown number of input variables or values (our output), an array-typed data type (collection) of any sort is a more flexible structure for your code. It is likely to require less maintenance in the end.
The Example: A Stored Procedure Search Query
Custom TYPE Definitions
CREATE OR REPLACE TYPE "COURSE_REC_TYPE" IS OBJECT (DEPID NUMBER(10,0), COURSE VARCHAR2(10));
CREATE OR REPLACE TYPE "COURSE_TBL_TYPE" IS TABLE of course_rec_type;
PROCEDURE Source Code
create or replace PROCEDURE ZZ_PROC_COURSE_SEARCH IS
my_input course_tbl_type:= course_tbl_type();
my_output course_tbl_type:= course_tbl_type();
cur_loop_counter pls_integer;
c_output_template constant varchar2(100):=
'DEPID: <<DEPID>>, COURSE: <<COURSE>>';
v_output VARCHAR2(200);
CURSOR find_course_cur IS
SELECT crs.depid, crs.course
FROM zz_course crs,
(SELECT depid, course
FROM TABLE (CAST (my_input AS course_tbl_type))
) search_values
WHERE crs.depid = search_values.depid
AND crs.course = search_values.course;
BEGIN
my_input.extend(2);
my_input(1):= course_rec_type(1, 'A');
my_input(2):= course_rec_type(4, 'D');
cur_loop_counter:= 0;
for i in find_course_cur
loop
cur_loop_counter:= cur_loop_counter + 1;
my_output.extend;
my_output(cur_loop_counter):= course_rec_type(i.depid, i.course);
end loop;
for j in my_output.first .. my_output.last
loop
v_output:= replace(c_output_template, '<<DEPID>>', to_char(my_output(j).depid));
v_output:= replace(v_output, '<<COURSE>>', my_output(j).course);
dbms_output.put_line(v_output);
end loop;
end ZZ_PROC_COURSE_SEARCH;
Procedure OUTPUT:
DEPID: 1, COURSE: A
DEPID: 4, COURSE: D
Statement processed.
0.03 seconds
MY COMMENTS: I wasn't particularly satisfied with the way the input variables were stored. There was a clumsy kind of problem with "loading" values into the nested table structure... If you can consider using a single search key instead of a composite pair (i.e., depid and course), the problem condenses to a simpler form.
Revised Cursor Using a Single Search Value
This is the proposed modification to the table design of the OP. Add a single unique key id column (RecId) to represent each unique combination of DepId and Course.
Note that the RecId column represents a SURROGATE KEY which should have no internal meaning aside from its property as a uniquely assigned value.
Custom TYPE Definitions
CREATE OR REPLACE TYPE "NUM_TBL_TYPE" IS TABLE of INTEGER;
Remove Array Variable
This will be passed directly through an input parameter from the procedure call.
-- REMOVE
my_input course_tbl_type:= course_tbl_type();
Loading and Presenting INPUT Parameter Array (Nested Table)
The following can be removed from the main procedure and presented as part of the call to the procedure.
BEGIN
my_input.extend(2);
my_input(1):= course_rec_type(1, 'A');
my_input(2):= course_rec_type(4, 'D');
Becomes:
create or replace PROCEDURE ZZ_PROC_COURSE_SEARCH (p_search_ids IN num_tbl_type) IS...
and
my_external_input.extend(2);
my_external_input:= num_tbl_type(1, 4);
Changing the Internal Cursor Definition
The cursor looks about the same. You can just as easily use an IN-LIST now that there is only one search parameter.
CURSOR find_course_cur IS
SELECT crs.depid, crs.course
FROM zz_course_new crs,
(SELECT column_value as recid
FROM TABLE (CAST (p_search_ids AS num_tbl_type))
) search_values
WHERE crs.recid = search_values.recid;
The Actual SEARCH Call and Output
The searching portion of this operation is now isolated and dynamic. It does not need to be changed. All the Changes happen in the calling PL/SQL block where the search ID values are a lot easier to read and change.
DECLARE
my_input_external num_tbl_type:= num_tbl_type();
BEGIN
my_input_external.extend(3);
my_input_external:= num_tbl_type(1,3,22);
ZZ_PROC_COURSE_SEARCH (p_search_ids => my_input_external);
END;
-- The OUTPUT (Currently set to DBMS_OUT)
DEPID: 1, COURSE: A
DEPID: 4, COURSE: D
DEPID: 7, COURSE: G
Statement processed.
0.01 seconds
This is something I havee used in the past in a situation similar to yours. Hopefully it helps.
The main benefit of this method would be that if you only passed it a single paramter it would still return all records for that single parameter. This way a single stored procedure with 5 input parameters could be used to search for all combinations of inputs.
Just call the stored procedure passing in the set and should return all values mathcing the criteria
usp_custom_search '1','A'
usp_custom_search '4','D'
usp_custom_search '4',NULL
usp_custom_search NULL,'A'
etc
Stored Procedure:
CREATE OR REPLACE PROCEDURE custom_search (
dep_id IN VARCHAR2,
course_id IN VARCHAR2,
result_set OUT SYS_REFCURSOR)
BEGIN
query_str VARCHAR2(1000);
query_str := 'SELECT';
query_str := query_str || ' DepId, Course';
query_str := query_str || ' FROM Course';
query_str := query_str || ' WHERE 1=1';
IF (dep_id is not null) then query_str := query_str || ' AND DepId = ''' || dep_id || ''''; END IF;
IF (course_id is not null) then query_str := query_str || ' AND Course = ''' || course_id || ''''; END IF;
open result_set for query_str;
END custom_search;
/
I'm new to PL-SQL, and struggling to find clear documentation of operations are nested tables. Please correct any misused terminology etc.
I have a nested table type that I use as a parameters for a stored procedure.
CREATE OR REPLACE TYPE "STRARRAY" AS TABLE OF VARCHAR2 (255)
In my stored procedure, the table is initialized and populated. Say I have a VARCHAR2 variable, and I want to know true or false if that varchar exists in the nested table.
I tried
strarray.exists('somevarchar')
but I get an ORA-6502
Is there an easier way to do that other than iterating?
FOR i IN strarray.FIRST..strarray.LAST
LOOP
IF strarray(i) = value THEN
return 1;--found
END IF;
END LOOP;
For single value check I prefer the "member" operator.
zep#dev> declare
2 enames strarray;
3 wordToFind varchar2(255) := 'King';
4 begin
5 select emp.last_name bulk collect
6 into enames
7 from employees emp;
8 if wordToFind member of enames then
9 dbms_output.put_line('Found King');
10 end if;
11 end;
12 /
Found King
PL/SQL procedure successfully completed
zep#dev>
You can use the MULTISET INTERSECT operator to determine whether the string you're interested in exists in the collection. For example
declare
l_enames strarray;
l_interesting_enames strarray := new strarray( 'KING' );
begin
select ename
bulk collect into l_enames
from emp;
if( l_interesting_enames = l_interesting_enames MULTISET INTERSECT l_enames )
then
dbms_output.put_line( 'Found King' );
end if;
end;
will print out "Found King" if the string "KING" is an element of the l_enames collection.
You should pass an array index, not an array value to an exists in case you'd like to determine whether this element exists in collection. Nested tables are indexed by integers, so there's no way to reference them by strings.
However, you might want to look at associative arrays instead of collections in case you wish to reference your array element by string index. This will look like this:
DECLARE
TYPE assocArray IS TABLE OF VARCHAR2(100) INDEX BY VARCHAR2(100);
myArray assocArray;
BEGIN
myArray('foo') := 'bar';
IF myArray.exists('baz') THEN
dbms_output.put_line(myArray('baz'));
ELSIF myArray.exists('foo') THEN
dbms_output.put_line(myArray('foo'));
END IF;
END;
Basically, if your array values are distinct, you can create paired arrays referencing each other, like,
arr('b') := 'a'; arr('a') := 'b';
This technique might help you to easily look up any element and its index.
When a nested table is declared as a schema-level type, as you have done, it can be used in any SQL query as a table. So you can write a simple function like so:
CREATE OR REPLACE FUNCTION exists_in( str VARCHAR2, tab stararray)
RETURN BOOLEAN
AS
c INTEGER;
BEGIN
SELECT COUNT(*)
INTO c
FROM TABLE(CAST(tab AS strarray))
WHERE column_value = str;
RETURN (c > 0);
END exists_in;