# Uniqueness **The number of records that can be identified uniquely based on a predefined key.** {% hint style="info" %} **Good to know:** Uniqueness is the inverse of duplicates. {% endhint %} ![](https://3733073204-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FQqDFwuhvqfmvmrkgivf1%2Fuploads%2FgzCFil3KLviiGp7bZOyb%2FUntitled%20presentation%20\(2\).png?alt=media\&token=152ecdfa-560b-4211-967d-2972b2c80245) ## **Measuring Uniqueness** **Prerequisite for this is that primary key defined** Formula : 1 – primary\_key\_count / total\_row\_count **Common unit of Measure:** Value count or percentage ## **Examples** Three different problems uniqueness could have occurred: One record with one key value occurs more than once in a dataset (duplicate with identical key values). The two records are not unique. Key | Student Name 22 | John snow 22 | John snow Often times Datastore constraints can easily help avoid this issue. Multiple records with same values occur more than once in a dataset (duplicate with different key values). Object John is not unique in the dataset. Key | Student Name 22 | John snow 37 | John snow A record has the same key as another record, and both occur in a dataset (false duplicate). Key 22 is not unique. Key | Student Name 22 | John snow 37 | John snow Most often users will need use sophisticated **master data management and Identify resolution systems** for resolving duplicates like these. **Related dimension:** Consistency --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.telm.ai/academy/data-quality-indicators/uniqueness.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.