DocType Naming and Linking

Then let us create the other DocType and save it too:

Library Member (First Name, Last Name, Email Address, Phone, Address)

Doctype Saved

Naming of DocTypes

DocTypes can be named in different ways:

Based on a field
Based on a series
By controller (code)
Prompt

This can be set by entering the Autoname field. For controller, leave blank.

Search Fields: A DocType may be named on a series but it still needs to be searched by name. In our case, the Article will be searched by the title or the author name. So this can be entered in search field.

Autonaming and Search Field

Link and Select Fields

Foreign keys are specified in Frappe as Link type fields. The target DocType must be mentioned in the Options text area.

In our example, in the Library Transaction DocType, we have to link both the Library Member and the Article.

Note: Remeber that Link fields are not automatically set as Foreign Keys in the MariaDB database, because that will implicitly index the column. This may not be optimum hence the Foreign Key validation is done by the Framework.

Link Field

For select fields, as we mentioned earlier, add the various options in the Options input box, each option on a new row.

Select Field

Similary complete making the other models.

Linked Values

A standard pattern is when you select an ID, say Library Member in Library Membership, then the Member's first and last names should be copied into relevant fields in the Library Membership Transaction.

To do this, we can use Read Only fields and in options, we can set the the name of the link and the fieldname of the property we want to fetch. For this example in Member First Name we can set library_member.first_name

Fetch values

Complete the Models

In the same way, you can complete all the models so that the final fields look like this: