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Data Science & Analytics vocabulary · SQL and Querying

Primary key

Meaning in data science & analytics, with examples

nounCommon term

In data science & analytics, primary key means: A column, or a set of columns, whose value is unique for every row in a table and is used to identify each row, such as an order ID.

In Turkish: birincil anahtar

How it is used

Shortened to PK in diagrams and casual talk. A primary key cannot be empty or repeated. When the same column appears in another table to link the two, it is called a foreign key there. Analysts check the key first when counts look wrong.

Example sentences

  1. The primary key of this table is order_id, so every order should appear only once.

  2. This events table has no primary key, which is why we keep finding duplicates.

Common collocations

  • primary key column
  • foreign key
  • unique primary key
  • composite primary key
  • joinAn operation that combines rows from two or more tables using a shared column, such as a customer ID; as a verb, to combine tables in this way.
  • duplicateA record that appears more than once in a dataset, for example the same customer or order stored twice, which can make counts and totals too high.
  • schemaThe structure of a database or dataset: which tables exist, which columns they have, the data type of each column and how the tables relate to each other.
  • granularityThe level of detail in data, meaning what one row represents, for example one row per order, per customer per day or per store per month.

This word in other fields

The same English word can have a different meaning in another field:

More terms: SQL and Querying

Practise with graded reading

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