Metadata is data about your data. For example, you might decide that one or more of the following types of information about your dataset should be tracked:
This section provides some methods for how to insert metadata into your dataset.
You can insert the row number in the source file from which rows in your dataset are sourced, using the
Tip: Source row number information can be lost when multi-dataset operations, such as unions and joins, are performed on your dataset. These steps should be added very early in your recipe.
In your recipe, insert the following transformation:
For more information, see Source Metadata References.
Tip: You can derive the current row number in your dataset. For more information, see ROWNUMBER Function.
The following example describes how to insert a single column of metadata. In this case, the full path to the source is inserted as a new column in the dataset.
In the Dataset Details page, select the entire value for the Location, which is the storage location of the source.
Tip: If the full path of the dataset is too long for screen display, be sure to include the ellipsis (...) at the end of the Location value.
Copy the value. Paste the value into a text editor. You should see the full path, like the following:
<root_dir>/uploads/1/2580298d-3477-4907-bfa7-f71978eace04/SF Restaurants - businesses.csv
Specify the following transformation:
You might need to track more fields of dataset information. While you might be able to perform these kinds of individual inserts, it might be easier to build this information from a separate file.
NOTE: This method uses the FILL function, which should be limited to smaller datasets when applied with a single key. Otherwise, there might be performance impacts when running the job against the full dataset.
Tip: You can perform a similar merging of datasets using the Join tool. See Join Window.
For example, you want to track the following fields as metadata:
You could create a CSV file that looks like the following:
source_system,source_author,source_date_create Excel,Joe Guy,12/9/15
In this case, the column headers are in the first line, and the values for each column are in the second line.
headertransform to your recipe.
In the recipe panel of the Transformer page, add a new step. In the Transformation textbox, enter
Sort your data by a key value (e.g.
Determine an appropriate grouping parameter. This step is necessary to simplify the filling process when the job runs at scale. Ideally, you should choose a grouping column that contains a relative few number of values in it (e.g.
Fill values in the data rows with metadata column values. For each metadata column, add the following transformation, done here for the
source_system column of metadata.
Repeat the above step for each metadata column you want to insert.
windowcolumns to use a more appropriate name.