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Retrieving data before insert statement in procedure

BufossJul 19 2015 — edited Jul 20 2015

Hi,
I am new in plsql programming and I would like to make a procedure.I have tables like the following TABLE1

|COL1 | COL2 | COL3 | COL4 | COL5 | COL6 |COL7|
| 600 | 140 | 2 | 10 | 1300 | 500 | 1 |
| 600 | 140 | 2 | 20 | 1400 | 340 | 4 |
| 600 | 140 | 2 | 15 | 1400 | 230 | 3 |
| 600 | 140 | 2 | 35 | 1700 | 120 | 2 |
| 600 | 150 | 3 | 10 | 1300 | 166 | 6 |
| 600 | 150 | 3 | 15 | 1400 | 435 | 5 |

For the same COL1 and COL2/COL3 , check the select different values from COL4
For instance for COL1=600 , COL2=140/COL3=2 and COL2=150/COL3=3
Return 20 and 35 as not common values


Then insert in this table TABLE1 the rows
600 , 150 , 3, 20 , 1400 , 340, 7
600 , 150 , 3, 35 , 1700 , 120, 8


I am trying to make the procedure like below but I have problem how to retrieve data in insert statement

PROCEDURE COPY_COLUMNS  ( P_COL1        IN  A.COL1%TYPE,

                          P_FROM_COL2   IN  B.COL2%TYPE,

                          P_FROM_COL3   IN  B.COL3%TYPE,

                          P_TO_COL2     IN  B.COL2%TYPE,

                          P_TO_COL3     IN  B.COL3%TYPE,

                          P_FLG1        IN  VARCHAR2,

                          P_FLG2        IN  VARCHAR2,

                          P_FLG3        IN  VARCHAR2                                     

                                     ) IS

CURSOR CFL1 IS select COL4

    FROM TABLE1

    WHERE COL1 = P_COL1 AND COL2 = P_FROM_COL2 AND COL3 = P_FROM_COL3

    MINUS

    select COL4

    FROM TABLE1

    WHERE COL1 = P_COL1 AND COL2 = P_TO_COL2 AND COL3 = P_TO_COL3;

CURSOR CFL2 IS select COL4

    FROM TABLE2

    WHERE COL1 = P_COL1 AND COL2 = P_FROM_COL2 AND COL3 = P_FROM_COL3

    MINUS

    select COL4

    FROM TABLE2

    WHERE COL1 = P_COL1 AND COL2 = P_TO_COL2 AND COL3 = P_TO_COL3;

CURSOR CFL3 IS select COL4

    FROM TABLE3

    WHERE COL1 = P_COL1 AND COL2 = P_FROM_COL2 AND COL3 = P_FROM_COL3

    MINUS

    select COL4

    FROM TABLE3

    WHERE COL1 = P_COL1 AND COL2 = P_TO_COL2 AND COL3 = P_TO_COL3; 

V_REC        CFL1%ROWTYPE;

BEGIN

IF P_FLG1='N' OR P_FLG2='N' OR P_FLG3='N' THEN

    GOTO label; --do nothing

END IF;

IF P_FLG1 = 'Y' THEN

    OPEN CFL1;

    FETCH CFL1 INTO V_REC;

    CLOSE C1;

--    SELECT COL5, COL6

--    FROM TABLE1

--    WHERE COL1 = P_COL1 AND COL2 = P_FROM_COL2 AND COL3 = P_FROM_COL3 AND COL4 = V_REC.COL4;

    FOR REC IN CFL1 LOOP

        INSERT INTO TABLE1

            SELECT P_COL1, P_TO_COL2, P_TO_COL3, CFL1.COL4, -- COL5 ?? , COL6 ?? -- , SEQname2.NEXTVAL)

    END LOOP;

END IF;

<<label>>

END;

Could you help me please do it ?
Thanks in advance

This post has been answered by Solomon Yakobson on Jul 19 2015
Jump to Answer

Comments

_AZ_

i think i should elaborate that I do expect to receive only one row ( from the select). Anything more (or less) should be deemed an error.

Answer

Well, with the code you have above you *will* get an error: TypeError: 'NoneType' object is not iterable. The reason for that is that fetchone() returns None if there are no rows left to fetch. That error isn't too helpful, though. You will need to do something along these lines:

row = cursor.fetchone()

if row is None:

   raise Exception("Hey, only one row was returned!")

tim, val = row

You will want to replace the Exception message with something a bit more meaningful, of course!

Marked as Answer by _AZ_ · Sep 27 2020
_AZ_

thank you @Anthony . Is there a better approach that i should.could use ( vs fetchone or overall ) ?

You're welcome. That approach works and is reasoanble. If you want to check for too many rows as well, you can do fetchall() which will return an array and check the length of the array instead. If you're worried about getting back too many rows with fetchall() you can also use fetchmany(2) which will tell you if there are 0, 1, or 2 rows available.

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Locked on Aug 17 2015
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