# 13.5: Types of Table Relationships

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Learning Objectives

• Define one-to-one relationships
• Define one-to-many relationships
• Define many-to-many relationships

There are three types of relationships in Access between tables:

• One-to-one
• One-to-many
• Many-to-many

## One-to-One Relationships

A one-to-one relationship means that a record in the first table can have one and only one record related to it in a second table. For example, a product listed in a products table would have only one country of origin record in a operations table.

## One-to-Many Relationships

One of the most common relationships between tables is the one-to-many relationship. In a one-to-many relationship, a record in the first table is related to multiple records in the second table. For example, an employee table could have relationships with a payroll table that contains multiple records of paychecks.

## Many-to-Many Relationships

Many-to-many relationships are defined as a record in the first table having multiple relationships in the second table and those records in the second table also having multiple relationships within the first table. For example, a streaming service would have TV series that are selected to view by multiple customers while each customer of the service would watch multiple TV series.