# Adding fields
# Understanding Schemas
Jira stores its data in a series of database tables. In order to query the data, Seatbelt retrieves this project data, a table or view at a time. Each of these extracts becomes a "schema" which can then be used in Seatbelt queries. Each schema in Seatbelt for Jira provides a list of fields that you can select in your query. This gives you the ability to build powerful rules by setting conditions on the data. The schemas also contain information about the relationships between fields, which can be used to further refine your queries. By taking advantage of these features, you can make sure that your rules are based on accurate and up-to-date data. As a result, you'll be able to confidently make decisions about your projects using Seatbelt for Jira.
# Select fields from a schema
From issues schema
SELECT id FROM issues
From boards schema
SELECT id FROM boards
From sprints schema
SELECT id FROM sprints
From projects schema
SELECT id FROM projects
From versions schema
SELECT id FROM versions