Topic
6 replies Latest Post - ‏2012-09-10T12:51:35Z by GlenSakuth
SystemAdmin
SystemAdmin
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Pinned topic CDC for Column update in Oracle

‏2012-09-06T17:13:54Z |
Hi,

We are finding softwares on doing CDC on data update on column in Oracle database. Some CDC softwares can only monitor update on entire row such that some rows are captured because of updates in un-related columns in a row.

Does any expert here know the InfoSphere CDC can do the column field monitoring in a table? Such that only defined column(s) are covered in
capture processes, in case the column(s) are updated, that data row
is captured.

Thanks for your information in advance,

Raymond
Updated on 2012-09-10T12:51:35Z at 2012-09-10T12:51:35Z by GlenSakuth
  • GlenSakuth
    GlenSakuth
    9 Posts
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    Re: CDC for Column update in Oracle

    ‏2012-09-06T17:38:56Z  in response to SystemAdmin
    Hi,

    InfoSphere CDC has the concept of a critical column. If you only want the row replicated if specific columns are changed, you would specify those columns as critical. By default InfoSphere CDC will consider all columns as critical for any selected table (in other words by default if any column changes then the row will be replicated).
    • SystemAdmin
      SystemAdmin
      61 Posts
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      Re: CDC for Column update in Oracle

      ‏2012-09-07T04:40:37Z  in response to GlenSakuth
      Hi GlenSakuth,

      Thanks for your information first.

      May I know if any public link for accessing the CDC for oracle documentation? I want to know more information about this.

      Or I need to contact our local sales for this?

      Thanks,
      • GlenSakuth
        GlenSakuth
        9 Posts
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        Re: CDC for Column update in Oracle

        ‏2012-09-07T12:14:54Z  in response to SystemAdmin
        Hi Raymond,

        All documentation for InfoSphere CDC is available online in the IBM Information Center. Here is the link to the site: http://publib.boulder.ibm.com/infocenter/iidr/v10r1m2/topic/com.ibm.cdcdoc.homepage_652.doc/ic-homepage-cdc_652.html

        General information such as what a critical column is and how to set them can be found in the Management Console (GUI) Administration guide. Specifics related to Oracle can be found in the InfoSphere CDC for Oracle Databases guide.

        Regards,

        Glen.
        • SystemAdmin
          SystemAdmin
          61 Posts
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          Re: CDC for Column update in Oracle

          ‏2012-09-10T03:52:36Z  in response to GlenSakuth
          Hi GlenSakuth,

          Thanks for your guideline and documentation link, may I ask two more questions? First question is, suppose I use CDC for Oracle to monitor 2 columns out of 10 columns in a table, then one new column is added to that table, can the CDC be alert for the new column in the table so that we need to take refresh on any settings?

          Second question, does CDC require to access the physical log files from Oracle? Or remote log scanning in which physical access to log file is disallowed? Because I found other CDC from other softwares may not require this priviege in Oracle.

          Thanks,
          Ray
          • GlenSakuth
            GlenSakuth
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            Re: CDC for Column update in Oracle

            ‏2012-09-10T12:44:10Z  in response to SystemAdmin
            Hi Raymond,

            Q1: CDC has built-in a capability called DDL awareness. If the DDL changes on a table being replicated, when the DDL is detected, replication will shutdown with a message that there was DDL. Then you can update the mapping as appropriate, and refresh the contents of that one column, and restart replication.

            Q2: For simplicity, The vast majority of InfoSphere CDC clients use the configuration to read the logs directly on the DB server. However, there are other mechanisms such as remote log reading off of a shared disk, as well as options for log shipping to another system that can be used.

            Regards,

            Glen.
          • GlenSakuth
            GlenSakuth
            9 Posts
            ACCEPTED ANSWER

            Re: CDC for Column update in Oracle

            ‏2012-09-10T12:51:35Z  in response to SystemAdmin
            Hi Raymond,

            Q1: CDC has built-in a capability called DDL awareness. If the DDL changes on a table being replicated, when the DDL is detected, replication will shutdown with a message that there was DDL. Then you can update the mapping as appropriate, and refresh the contents of that one column, and restart replication.

            Q2: For simplicity, The vast majority of InfoSphere CDC clients use the configuration to read the logs directly on the DB server. However, there are other mechanisms such as remote log reading off of a shared disk, as well as options for log shipping to another system that can be used.

            Regards,

            Glen.