> ## Documentation Index > Fetch the complete documentation index at: https://docs.xano.com/llms.txt > Use this file to discover all available pages before exploring further. # Relationships > Database Relationships are used to define related data between one or more tables. **Quick Definition** Database relationships show how different tables of data connect to each other - like how a customer's ID links their personal information to their complete order history. These relationships can be one-to-one (one person, one social security number), one-to-many (one customer, many orders), or many-to-many (many students can take many classes). ## 🧑‍🤝‍🧑 Types of Relationships In Xano, there are three primary ways tables can be related: #### 1. One-to-One This is like a person and their unique passport. Each data entry in one table relates to exactly one entry in another table. #### 2. One-to-Many Think of a parent and their children. A single entry in one table can relate to multiple entries in another. For example, one teacher can teach many students. #### 3. Many-to-Many Similar to students enrolling in various courses, any entry in one table can relate to multiple entries in another. *** ## ❓ Why Use Relationships? * **Data Consistency**: Ensures all references are valid. * **Reduced Redundancy**: Minimizes repeated data. * **Efficient Data Retrieval**: Makes it easier to access related data. Understanding these basic concepts can simplify how you view databases and highlight why tools like Xano are powerful for managing data. *** ## 👀 Using the Table Reference Field Type When you add a table reference field to a database table, that field simply stores the IDs of the record(s) being referenced; the data is not actually duplicated. To access the actual data is typically done via an add-on as part of a function stack. ### Auto-Complete Auto-Complete allows you to configure how the referenced records look inside of other tables. For this example, we have two tables: `user` and `userRole`