How do you handle null in Datastage?
You can use the null handling functions in the Transformer stage to handle nulls in derivations. If you use input columns in an output column expression, a null value in any input column causes a null to be written to the output column. You can, however, use the null handling functions to handle nulls explicitly.
How do you handle null values in sequential file in Datastage?
Open Sequential File—> Go to Format—>click on Field Defaults—>bottom right side you will find AVAILABLE Properties to ADD, Under that select, “NULL FIELD VALUE” and give the value as ” 0″ [zero]. You’ll get the Null records in your output sequential file. they are handled first.
What is null to value in Datastage?
NullToValue. Returns the specified value if the input column is null, otherwise returns the input column value. Examples. If the Derivation field for an output column contained the following code, then the Transformer stage checks if the input column named mylink.
What happens when we pass NULL values to sequential file stage?
DataStage has a mechanism for denoting NULL field values. It is slightly different in server and parallel jobs. In the sequential file stage a character or string may be used to represent NULL column values.
What is the use of Transformer in DataStage?
The Transformer stage is a processing stage. It appears under the processing category in the tool palette. Transformer stages allow you to create transformations to apply to your data. These transformations can be simple or complex and can be applied to individual columns in your data.
What is derivation DataStage?
Derivation – Expression that specifies value to be passed on to the target column. Constant – Conditions that are either true or false that specifies flow of data with a link.
How do I remove duplicates in DataStage?
The data set input to the Remove Duplicates stage must be sorted so that all records with identical key values are adjacent. You can either achieve this using the in-stage sort facilities available on the Input page Partitioning tab, or have an explicit Sort stage feeding the Remove Duplicates stage.
What is surrogate key in DataStage?
A surrogate key is a unique primary key that is not derived from the data that it represents, therefore changes to the data do not change the primary key. In a star schema database, surrogate keys are used to join a fact table to a dimension table.
What are stage variables in Datastage?
-Stage Variables : A stage variable is an intermediate processing variable which is used to retain the generated values during reading. They does not pass on to the target column.
How do I copy a column name in Datastage?
This can be a range of Column Names selected while holding the SHIFT key or individual Column Names selected holding the CTRL key. Next we right click on the Column Name for the row that has the attributes we are copying from (The STATUS row in this example) and select Propagate Values from the Menu.
How do you remove duplicates without using duplicate stage in DataStage?
There are multiple ways to remove duplicates other than using Remove Duplicates Stage. As stated above you can use Sort stage, Transformer stage. In sort stage, you can enable Key Change() column and it will be useful to filter the duplicate records. You can use Aggregator stage to remove duplicates.
How do I capture duplicate records in DataStage?
You can capture the duplicate records based on keys using Transformer stage variables.
- Sort and partition the input data of the transformer on the key(s) which defines the duplicate.
- Define two stage variables, let’s say StgVarPrevKeyCol(data type same as KeyCol) and StgVarCntr as Integer with default value 0.