Configuring Delete Service

About this task

A Delete service deletes the record from the Cassandra table. You configure Delete service using Designer. For more information about adapter services, see Using Adapter Services.

Read the section Before Managing Adapter Services, before you configure adapter services.

To configure an adapter service using the Delete template:

Procedure

  1. In Designer, right-click the folder in which the service is to be contained and select New > Adapter Service.
  2. Select the parent namespace, type a name for the adapter service, and click Next.
  3. Select IBM webMethods Adapter for Apache Cassandra as the adapter type and click Next.
  4. Select the appropriate Adapter Connection Name and click Next.
  5. From the list of available templates, select the Delete template and click Finish.
    The adapter service editor for the selected adapter service appears. You can select the Adapter Settings tab at any time to confirm Adapter Properties such as the Adapter Name, Adapter Connection Name, and Adapter Service Template as necessary.
  6. Select the Table tab to configure the table and set the fields as follows:
    Field Field Description/Action
    Keyspace Name Specifies the keyspace which is auto-populated based on the created connection.
    Table Name Specify the name of the table.
  7. Use the Columns tab to provide values for the following fields:
    1. Use the icon to populate a single column in the table. You can use the icon to display all columns created in an existing table.
      Field Description/Action
      Column Name The column name in the table.
      Column Type The column data type defined in the corresponding Column Name of the table.
      Type Definition Specifies the string representation of Column Type.
  8. Use the Options tab to provide the appropriate values for the following fields:
    Field Description/Action
    Consistency Level Defines to manage availability versus data accuracy. You can configure consistency for a session or per individual read or write operation.
    The write consistency levels in strongest-to-weakest order is given as follows:
    • ALL: Provides the highest consistency and the lowest availability of any other level.
    • EACH QUORIUM: Maintains a strict consistency level at the same level, when used in multiple datacenter clusters.
    • QUORIUM: Maintains a strong consistency across the cluster, when used in either single or multiple datacenter clusters. Use QUORIUM, if you can tolerate some level of failure.
    • LOCAL QUORIUM: Maintains consistency locally. LOCAL QUORIUM is used in multiple datacenter clusters with a rack-aware replica placement strategy, such as (NetworkTopologyStatergy), and a properly configured snitch. Can be used with SimpleStrategy.
    • LOCAL ONE: In a multiple datacenter clusters, the consistency level cross-DC traffic is not desirable when compared to the consistency level of ONE. LOCAL ONE accomplishes this. Use this consistency level in an offline datacenter to prevent automatic connection to online nodes in other datacenters if an offline node goes down.
    • THREE: Satisfies the needs of most users because consistency requirements are not stringent.
    • ANY: Provides low latency and a guarantee that a write never fails. Delivers the lowest consistency and highest availability.
    The read consistency levels in strongest-to-weakest order is given as follows:
    • ALL: Provides the highest consistency of all levels and the lowest availability of all levels.
    • QUORIUM: Maintains strong consistency across the cluster, when used in single or multiple datacenter clusters. Ensures strong consistency if you can tolerate some level of failure.
    • LOCAL QUORIUM: Used in multiple datacenter clusters with a rack-aware replica placement strategy ( NetworkTopologyStrategy) and a properly configured snitch. Fails when used with SimpleStrategy.
    • THREE: Provides the highest availability of all the levels if you can tolerate a comparatively high probability of stale data being read. The replicas contacted for reads may not always have the most recent write.
    • LOCAL ONE: In a multiple datacenter clusters, the consistency level cross-DC traffic is not desirable when compared to the consistency level of ONE. LOCAL ONE accomplishes this. Use this consistency level in an offline datacenter to prevent automatic connection to online nodes in other datacenters if an offline node goes down.
    • SERIAL: Use SERIAL to read the latest value of a column after a user has invoked a lightweight transaction to write to the column. Cassandra then checks the inflight lightweight transaction for updates and, if found, returns the latest data.
    • LOCAL SERIAL: Used to achieve linearizable consistency for lightweight transactions.
    EnableTracing Define to enable and disable the tracing for transactions on all nodes in the cluster. Tracing is enabled to troubleshoot performance problems.
    If Exists Checks if columns value selected in WHERE clause is available and deletes the record and returns the success value as true else returns the value as false.
  9. Use the WHERE tab to specify the conditions for selecting information:
    1. Select the icon to define the new WHERE clause fields.
    2. Select the AND logical operator and specify the following fields:
      Field Name Description/Action
      AND The logical operator.
      Column

      The name of the column you want to use in the WHERE clause.

      Operator The following are the operators used:
      • =
      • IN
      Input Field The default value is ?, which acts as a placeholder for the variable so that you can set the input variable for that column at run time, or get input external to this adapter service. You can also type a fixed value in this field now or at run time. If you type a fixed value, be sure that it is valid, or an exception will be generated at run time.

      The adapter automatically generates values for the following fields:

      Field Description/Action
      Parameter The unique key for those rows in the above table which takes input at runtime.
      Column The name of the column you need to use in the WHERE clause.
      CQL Type The CQL data type defined in the corresponding Column Name of the table.
      Input Field Type The corresponding data type of the Input Field.
      Input Field The name of the input field. By default the name combines the values of Parameter and Column fields. However, you can also choose to specify any custom value.
  10. Use the If Clause tab to specify the if condition for the following:
    1. Select the icon to define the new If Clause fields.
    2. Select the AND logical operator and specify the following fields:
      Name Name Description/Action
      AND The logical operator.
      Column

      The name of the column you want to use in the If Clause.

      Operator The following are the operators used:
      • =
      • <
      • >
      • <=
      • >=
      • IN
      • CONTAINS
      • CONTAINS KEY
      Input Field The default value is ?, which acts as a placeholder for the variable so that you can set the input variable for that column at run time, or get input external to this adapter service. You can also type a fixed value in this field now or at run time. If you type a fixed value, be sure that it is valid, or an exception will be generated at run time.

      The adapter automatically generates values for the following fields:

      Field Description/Action
      Parameter The unique key for those rows in the above table which takes input at runtime.
      Column The name of the column you need to use in the WHERE clause.
      CQL Type The CQL data type defined in the corresponding Column Name of the table.
      Input Field Type The corresponding data type of the Input Field.
      Input Field The name of the input field. By default the name combines the values of Parameter and Column fields. However, you can also choose to specify any custom value.
      Note: If Not Exists field cannot be used with If Clause tab at the same time.
  11. To verify input or output information for the service, use the Input/Output tab as required.
    The below field is auto-populated in input section of Input/Output tab:
    Field Description/Action
    timestamp Specify the time of insertion of the record.
    Note: The remaining fields in the input section are auto-populated based on the columns selected in WHERE tab and If Clause tab.
    The below field is populated in the output section of Input/Output tab:
    Field Description/Action
    success Specifies the result of the service. It can either be true or false.
  12. From the File menu, select Save.