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Options | Description | |||||
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Template | Enables you to generate update procedures via a template. | |||||
Business Key Columns | Columns that define the business key for update processing. Required to include Update options. Clicking the ellipsis button brings up the Business Key selection screen. A business key can be made up of multiple columns, but it must provide a unique identifier. Where multiple columns separately uniquely identify rows in the EDW 3NF Object, choose one to act as the primary business key. For example, a source table may have a unique constraint on both a product code and a product description. Therefore the description as well as the code must be unique. It is possible to combine the two columns, but the normal practice would be to choose the code as the business key.
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Parameters | Any parameters selected are included in the generated update procedure as variables. The procedure includes code to retrieve the value of the parameter at run time and store it in the declared variable. Clicking the ellipsis button brings up the Parameters selection screen. The variables can also be used in column transformations and in the from/where clause for the update procedure. Some databases have a 30 character limit for variable names. WhereScape RED ensures the variables added for any parameters are less than 30 characters long by creating variable names in the form v_ followed by the first 28 characters of the parameter name. For example, a parameter called MINIMUM_ORDER_NUMBER_SINCE_LAST_SOURCE_LOAD will be available as the variable v_MINIMUM_ORDER_NUMBER_SINCE_L.
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Include Initial Load Insert | Adds insert statement to the update procedure that runs if the target EDW 3NF object is empty. The benefit of this is improved performance inserting into an empty table without performing any checks to see if rows already exist. The default for this field is off (i.e. an initial insert statement is not added to the procedure). | |||||
Process by Batch | Enables you to select a column to drive data processing in a loop based on the distinct ordered values of the selected columns. The update procedure loops on this column and performs the delete, update and/or insert for each value. If the column chosen is a date data type (date, datetime or timestamp), then the user can specify yearly, monthly, daily or column level looping. The default for this field is off (do not do batch processing). | |||||
Delete Before Insert | Enables you to select how to process deletes. It enables a delete statement to be added to the update procedure before any update or insert statement. This is a particularly useful option for purging old data and for updates based on a source system batch number. If this option is selected, the following options are also available:
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Process Method | Select between Insert/Update and Merge which allows you to use the Merge statement instead of two separate Insert and update statements. | |||||
Include Insert Statement | Includes the insert statement in the procedure to insert new rows in the EDW 3NF Object.
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Insert New Rows Only | Uses change detection to work out what rows require inserting. | |||||
New Row Identification Method | Method used to identify that records in the source are not currently recorded in the target table. | |||||
Existing Data Selection Hint | Database-compliant hint to be used for the existing data select statement. | |||||
Include Update Statement | Includes an update statement in the procedure to update changing rows in the EDW 3NF Object. If this option is chosen, then the Update Changed rows only option is available.
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Update Changed Rows Only | Uses change detection to work out what rows require updating. Choosing this option, enables the Change Row identification Method. | |||||
Change Row Identification Method | Method used to identify that records in source have changed from what is currently recorded in the target table. | |||||
Existing Data Selection Hint | Database-compliant hint to be used for the existing data select statement.
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A simple join only returns rows where data is matched in both tables. So for example, if table A has 100 rows and table B has a subset of 24 rows. If all the rows in table B can be joined to table A then 24 rows will be returned. The other 76 rows from table A will not be returned.
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