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# Keys & Unique IDs

> Use unique values to make your apps more reliable.

In [Google Sheets](/docs/essentials/data-sources/google-sheets), rows don't really have an identity apart from their row number. In the image below we can see that the product **Part 3** is located in **row 4**.

![Google Sheet Row IDs](/docs/_fern-img/a843a0876d5b0862ba7b10dd974f1778cbbe09a69e6271640f85c1d084f5d6c6.webp)

This is fine, but if you add, move or delete rows, that row's location will change. In the image below, **Part 3** started off in **row 4,** but ends up in **row 3** after we delete a row.

![Google Sheet Unique ID 2](/docs/_fern-img/f65b72a93a4341f88ff1320297443dd0ac39a2143f2f1bce500ef38f8a699235.webp)

In some circumstances this is fine. But if you have [Components](/docs/essentials/components) like **Comments** and **Favorite** or use [Relations](/docs/automation/computed-columns/relations)—which need to know the exact location of a row and then the row number changes—these components will be confused or pull up incorrect data as they are only looking at row numbers.

## Unique Identifier

The way to solve this issue is by giving each row a **Unique Identifier**. In other words, a value in a column that will always be different and unique for each row. And the easiest way to do this in Glide is by using the [Row ID](/docs/automation/computed-columns/row-id-column) column in the [Data Editor](/docs/getting-started/introduction-to-the-data-editor).

If you don't have a Row ID column in your table, components like **Comments** and **Favorite** will ask you to set a Key or a Topic. This is a manual way for you to connect that component with a column of unique values in your sheet so it can keep track of that row. The Row ID column is the best way of doing this.