updating records
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Thread: updating records

  1. #1
    Join Date
    Jan 2009
    Posts
    11

    updating records

    I am trying to update the security_level of a mission to the highest security level of mimssions of the same type.

    Attributes of the missions table:
    mission_id, code_name, mission_type_id, mission_date, security_level

    The following is an intermediate output.
    MISSION_ID MISSION_TYPE_ID SECURITY_LEVEL
    318 3 6
    329 3 2
    286 5 6
    521 5 3
    281 6 4
    396 7 3
    331 8 4
    14 9 4
    230 9 0
    486 10 2


    The maximum output for each mission_type_id

    MAX_LEVEL TYPE
    6 3
    6 5
    4 6
    3 7
    4 8
    4 9
    2 10

    According to this 3 records (329,521 and 230) should update.

    But my code returns an error.
    ERROR at line 4:
    cannot update (......"SECURITY_LEVEL") to NULL

    can someone help meto find the fault?

    this is my code

    UPDATE
    AM_X_442_2 amx
    SET
    Amx.SECURITY_LEVEL =
    (
    select
    max_level
    from (
    select
    max(security_level) max_level,
    mission_type_id type
    from (
    SELECT
    mission_id,
    MISSION_TYPE_ID,
    security_level
    FROM
    (
    SELECT
    MISSION_ID,
    MISSION_TYPE_ID,
    SECURITY_LEVEL
    FROM
    AM_X_442_2 m
    WHERE
    LENGTH (SUBSTR (CODE_NAME, INSTR(CODE_NAME, ' ') +1)) > 7
    ORDER BY
    MISSION_DATE DESC
    )
    WHERE
    ROWNUM <=10
    GROUP BY
    mission_id,
    MISSION_TYPE_ID,
    security_level
    ORDER BY
    MISSION_TYPE_ID
    )
    GROUP BY
    MISSION_TYPE_ID
    ) ten_missions
    WHERE ten_missions.type = amx.MISSION_TYPE_ID
    )

  2. #2
    Join Date
    Mar 2007
    Location
    Ft. Lauderdale, FL
    Posts
    3,554
    I'm not sure if I got your specifications but something tells me your code is not even close of doing what you are supposed to do.

    Why you don't start by using pseudo-code so your specs would get clear and the logic could be reviewed?
    Pablo (Paul) Berzukov

    Author of Understanding Database Administration available at amazon and other bookstores.

    Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.

  3. #3
    Join Date
    Jul 2002
    Location
    Lake Worth, FL
    Posts
    1,445

    Thumbs down Spaguetti code anyone?

    Your code seems to have too much "garbage", try the code we suggested in your other post.
    "The person who says it cannot be done should not interrupt the person doing it." --Chinese Proverb

  4. #4
    Join Date
    Jan 2009
    Posts
    11
    It seems
    your subquery returns null value.
    check the subquery once

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