Identify the columns that together can uniquely identifier a row.Load the dataset into the Transformer page.Since there are multiple instances of test data for each person, there is no single column to use as a primary key. By far the simplest and most common technique for adding a primary key in Postgres is by using the SERIAL or BIGSERIAL data types when CREATING a new table. If your final dataset contains more than a few combined datasets, this basic method for creating a primary key is to find a combination of fields that collectively represent a unique identifier from the final dataset. Combine across datasetsĪfter you have combined or enriched your dataset, you can combine these original row ID fields from each dataset to create a super primary key in the combined dataset using the method described below. These steps should be applied across all datasets that you intend to combine into your output dataset. This method relies on these numbers for generating primary keys and is suitable when your final output contains a relatively few number of combined datasets. Hover over these dots to reveal the row numbers retrieved from the original source, if that information is still available. When a dataset is loaded into the Transformer page for the first time, you can see a set of black dots along the left side. This section provides two methods for generating primary keys in your datasets. Keep in mind that counts apply to the displayed sample, instead of the entire dataset. However, if you ever join with another dataset, you must re-review the suitability of the field and may need to build a new primary key field. If the numbers are equal, then the column is suitable for use as a primary key. 3) Creating a new table whose primary key has more than one column example. Tip: In the Transformer page, a quick way to check if there is a primary key in your dataset is to compare the count of categories in the data histograms for string-based data against the count of rows.
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