Comprehensive databases consist of several Libraries, and it’s a common thing when the entries in different Libraries are connected with each other. The related fields help create logical Library structure and do not duplicate the same entries.
There are three types of relationship that are used in database design: one-to-one, one-to-many and many-to-one. To learn more the difference, visit Linked fields article from Desktop section.
To create the relationship in Memento Database Mobile, click icon at the bottom-right of the window and choose Relationship option or select Link to entry field.
Relationship option allows you to choose the connected Library and set the default parameters, including many-to-many relation type. Anytime later you will be able to re-adjust the linking option. Click burger icon near the created field and choose Change option to set additional parameters: relation type, display options, dependencies, etc.
This is how the related fields are shown for the end user. The screenshot below shows the Product and all Sales for it:
Each linked field has additional attributes. Attributes are similar to fields but set more parameters for the linked field. For example, if we link the Products and Sales, we can define how many items of the chosen products were purchased during the single one sale using Integer attribute or the discount the customer got for the sale using Currency attribute. Attributes allow you to set the additional property that hasn’t been defined in any of the linked Libraries. After the attribute is added, the Library end user will need to define attribute value while adding the new entry to this Library.