How Knack Works
Design Your Database
Manage Your Records
Build Your Live Application
View and Share Your App
Do More With Knack
Connect Related Data
Users & Access
Calculations & Logic
Emails & Notifications
Search & Queries
Reporting & Dashboards
E-Commerce & Payments
Objects & Connections
Plan Your Connections: Complex Example
Working With Objects
Plan Your Connections: Simple Example
Plan Your Objects
Use Connections in Your App
Connecting Records Together
Connections: Troubleshooting & FAQs
Numeric Equation Functions
Date Equation Settings
Numeric Equation Settings
Text Formula Functions
CSV Format Guide for Importing
Working with Records
Deleting a Page That's Being Linked to
Working with Pages
Navigating the Page Preview
Printing Pages & PDFs
Table Column Settings
Source: Which Records Will the View Display
Using Action Links
Combining Fields from Connected Records in Views
Using Record Rules
Using Display Rules
Using Submit Rules
Users & Logins
Users and the Page Menu
Manage Roles & Permissions
Single Sign-On with Google, Facebook, Twitter, and Custom
Manage User Records
Logins and Registrations
Live App Security Settings: HIPAA Plans
Live App Security Settings
Tasks & Emails
How do I cancel my Knack account?
I'm over the storage limit for my account. How do I add more storage or get under the limit?
Need account access or to transfer account access because account owner or colleague left the company
I'm over the record limit for my account. How do I add more records or get under the limit?
Is there an option to pay via invoice, check, wire transfer, or something other than a credit card?
How do I freeze or pause my Knack account?
Where can I find a copy of my receipt or invoice?
How do I add more API calls to my account?
How do I change the favicon for my app?
How do I backup or export my apps and data?
How can I track what users are doing in my app?
How do I remove the "Powered by Knack" logo at the bottom of my app?
How do I give Builder access to a colleague or developer for one of my apps?
How do I white label my app?
How do I copy an app from my account to another account?
How do I show multiple dates on a calendar?
How do I add a logo to my app?
How do I find the most recent date from a connected object?
How do I create a field that always shows today's date?
Can I share or connect data between apps?
How do I create an "If, Then" or conditional equation?
How do I merge my apps, or copy pages, objects, or other app elements between my apps?
The menu isn't showing for my app on mobile devices. How do I fix that?
Is there a way to have new users be automatically logged-in after they register?
How do I bulk upload or import multiple files?
How do I move or copy fields or data from one object to another?
How can I show a customer's payment history if I'm collecting payments through my Knack app and through cash or check?
Is there a way to add a display rule to multiple columns at one time instead of having to update each column individually?
Do I need a separate user role object for my Vendors, Customers, Employees, Contacts, etc?
How can I set up my app so users see only their own data?
Can I combine two date fields into a single date field? For example, combining a start and end date into a single field?
Does Knack offer a service for building apps or have developers I can hire?
How do I bulk upload or import multiple images?
How can I change the color of something in my app?
Is it possible to display more than 100 records at a time on a table, list, or search view?
Can I migrate or transfer data from Zoho, Quickbase, or TrackVia?
Can I add chat or messaging to my app?
Can I sell my Knack apps?
Can I use Knack on mobile devices?
Do you have a sandbox or developer environment?
Can I send SMS or text messages using Knack?
Can I integrate Knack with other data, products, and services?
Can I create invoices and accept payments?
Can I have an app in a language besides English?
Can I email PDFs or other attachments to users with Knack?
Can I add Google Analytics to my Knack app?
Can I migrate my Access, Filemaker, SQL, or other databases?
Can I prototype for others?
Can I customize the look and feel of my Knack pages?
Can I use a barcode or credit card scanner with Knack?
Does Knack offer access to beta features?
How secure is Knack?
Does the signature captured through a signature field constitute a legally binding signature?
Does Knack offer a partner program?
How does Knack work on mobile devices? Is it mobile-friendly? Can users download my apps?
Is Knack GDPR compliant?
Storing sensitive data (credit cards, social security numbers, etc.)
Will Knack sign an NDA (Non-Disclosure Agreement)?
Which browsers do you support?
How do I batch download all of the images and files In my app?
I'm seeing an odd character when importing data. How can I get rid of it?
How do I update existing data using an import?
My import is failing or getting stuck. What do I do?
Can I undo or reverse an import?
I'm having trouble importing into a specific type of field. What can I do?
Some of my fields aren't importing correctly. How can I fix that?
I'm having trouble importing into a connection field. What can I do?
Can I import something other than data? Like objects, pages, views, etc?
My import is taking a long time. Can you take a look?
I'm getting an error when importing. What do I do?
Do the validation rules on fields trigger when importing data?
Can I schedule or automate imports?
Can my users import data from the live app, instead of going through the builder/back-end?
I am importing data for the first time. How do I do that?
Can I import data into more than one object at the same time?
How To Guides
Add Functionality to Your Live App
How To Create Discount Codes
Create an Add To Favorites Feature
How to Access Private Records Without a Login
Accept Payments in a Live App
Manage Your Records
Use an Edit Form to Create Records If They Don't Exist
Track Which User Last Updated a Record
Copy a Record Using Record Rules
Track When Records are Created and Updated
Create a Version History for Records
Use Zapier to Insert Connected Records
Work with Connected Records
How to Show Multiple Fields in Your Connection Drop-Down
Showing Parent-Child Records in the Live App
How to Create Dynamic Dropdowns in Forms
Add Read-Only Fields to a Form
How to Change the Layout of Forms
Create a Multi-Part Form
How to Allow Users to Add New Options in Forms
How to Add Instructions to a Form
How to Customize the Text on a Submit Button
How to Automatically Capture a User’s Location on a Form
How to Use URL Variables to Pre-Populate a Form
How to Add a Map to a Details View
How to Add Connection Links to Views
How to Add Inline Editing to a Table
Create a Print-Friendly Invoice Page
How to Click on an Image to Go to Another Page
How to Add Groupings to a Table
Users & Logins
Force Users to Reset Their Passwords
Save a User's Payment Method
Create a Single Login Page for Multiple User Roles
Add Read-Only Access For Users
Show Records Connected To The Logged-in User's Company Or Other Group
Show Records Connected to the Logged-in User
Create an Admin User Role to View All Records
Workflow & Automations
Add a Pipeline to Your App
Create a Registration Form with Limited Availability
Add Stages to Your App
Store Multiple Images or Files for Individual Records
Use Multiple Image Sources for a Single Image Field
Create a Button or Link that Updates a Field to a Custom Value
Notify a User That an Item is Ready for Review
Add Assignments to Your App
Approve New Records Before Displaying Them
Add Notification & Reminder Emails to Your App
Add Status Indicators to Your App
Logic, Equations & Formulas
Start an Auto Increment Field from Any Number
Display a Message When a Deadline is Approaching
Generate Simple Numeric Barcodes Automatically
How to Set a Random ID
Calculate Age in Years from a Birthday
How To Number Line Items
Show Upcoming Birthdays
How to Extract the Start and End Dates from a Date Field
How to Display Multiple Date Formats Using a Single Date Field
Reports, Queries, and Summaries
Build an Inventory Manager App
Build a Quiz App
Build a Warehouse Manager App
Build a Member Directory
Build an Orders App
Build a Map Directory or Store Locator App
Images & Files
Manage Your Account
Manage Your Account
About Knack Accounts
Account Plans and Billing
Managing Your Apps
Managing Your Account Settings
Sharing Apps with Shared Builders
App Settings: Map Provider
Script Attack Protection: Whitelisted Custom Code Elements and Attributes
Script Attack Protection: Protected Areas
Security & Infrastructure
Security Best Practices
Builder Security Settings for All Knack Plans
Builder Two-Factor Authentication
Table of Contents
- What is a Connection?
- Manage Connections
Updated by Danielle Kellogg
- What is a Connection?
- Manage Connections
What is a Connection?
Most apps will need more than one object. When this is the case, these objects will likely be related or connected to each other.
Here are some examples of when connections can be used:
- Many contacts can be connected to one company
- One order can be connected to many products
- Many managers can be connected to many projects
Knack defines these relationships with connections. Adding a connection means that records from one object can be connected to records from another object. These connections can be used throughout your app to add powerful functionality.
To use connections, you will need to have at least two objects. If you want to learn more about how to use objects you can read more here.
In the contact directory example app, we have two objects: Companies and Contacts. Each contact record is connected to a company record.
This means we can view a company record and add a view to show all the contact records connected to that company record.
The same app also has a Notes object, where each note record is connected to a contact record. This enables us to show notes records connected to each contact record.
To see more examples of how connections can be used in Knack, see this guide.
In the Schema section of the Builder when viewing an object's fields, each object has a Connections section along the right side of the Builder. Here you can add new connections to the object, as well as view any existing connection fields.
Add a Connection
To add a connection field, select an object in the Schema section of the Builder to view the fields list for that object. Once there, you can use the green "+" button in the right column to add a new connection field.
This will present a new window where you select the object you want the connection to connect to:
Once you have selected the object for your connection, next you define how that connection will work. When defining how the connection will work, you can choose from three main connection types, one-to-one, one-to-many and many-to-many.
For example, here are what these connection types would look like when using the objects Contact and Company.
- One-to-One: a connection where each Contact record connects to one Company record and each Company record connects to one Contact records.
- One-to-Many: a connection where each Contact record connects to one Company record and each Company record connects to many Contact records.
- Many-to-Many: a connection where each Contact record connects to many Company records and each Company record connects to many Contact records.
Once you have selected which connection type to use, click "Add Connection" and a connection will be added to the object. When you add a new connection, it creates a special connection field in that object:
These fields can be used like any other field throughout your app. If you add a connection field to a form, it will operate like a lookup, so you can select a specific record from the connected object to connect to.
Which Object to Add Your Connection To
You only need to add one connection field to create a connection between two objects, so which object should you add that field to?
For one-to-one and many-to-many relationships, we suggest placing the connection field on whichever object will be used or edited more frequently. This will affect where the connection field lookup will appear and make it easier to edit with a form view.
In a one-to-many relationship, in most cases, it is best practice to add the connection to the object with many connections. Or to put it another way, in a parent-child relationship, it works best to add the connection to the child object.
For example, in our Job Listings example app, one Job can connect with many Applications, so it will work best to add the connection to the Application object. This way, when we're editing or viewing an Application record, we can easily see which Job it’s connected to.
Here's what that connection will look like in a form when it's added to the Application object (or the child object). The connection field to the Job object will appear as a lookup field:
In this example, the application is connected to the "Lead Engineer" Job. You can change which Job it is connected to with the lookup (also called drop-down) field.
Next, here's what it would look like if the connection field was added to the Job object (or the parent object). Instead of connecting to one record it would need to connect to many or all the Application records:
Another reason the child object generally works best is that you'll typically create the parent records first. So when adding a child record, you'll have some parent records already created that you can connect to.
Edit a Connection
To make changes to an existing connection field, navigate to the Schema section of the Builder and locate the connection in the object's fields. Click on the "..." more options icon to choose the field settings.
Or open the field options and select the "Edit field settings" option while viewing the records in the Records section of the Builder:
Next, a popup with the connection field options will open.
Here you will be able to change the connection type as well as other basic field settings:
- Name: This changes the name of the field in your Builder.
- Description: This is a description which can be used to describe the field internally. These will show up as tooltips when viewing records in the Records section of the Builder.
- Required: This makes the field a required field.
- Default: Choose the default option that will display in your connection field when live.
- Connection: Change the connection type.
- Format: Choose between connection values displaying in a searchable dropdown or as radio buttons in your Live App.
Delete a Connection
Deleting connections should be done with caution because they are the basic building blocks in your app's foundation.
If you need to delete a connection, navigate to the Schema section of the Builder and locate the connection you would like to delete from the object's fields. On the connection field, click the "..." more options icon, then click "Delete". This will remove the connection field from the app.
You can also open the field options and select the "Delete field" option while viewing the records in the Records section of the Builder:
Use Connections in Your App
There are so many super powerful ways to use connections in your app. So many in fact, that this information needs its own article: Use Connections in Your App.
Notes & Troubleshooting
- Only one connection field is needed to link two objects. However, there are rare cases when using two connection fields between two objects is needed.
- When adding connection fields, it is best to place the connection field on the "many" object. This means for one-to-many connections, place the connection on the object which will have many records connected. For many-to-many connections, place the connection field on whichever object is used most often.
- If you have a connection field but connected records are not showing, double check the connection to make sure there is a value in the field. You can read more about troubleshooting connections here.
Warning: Edit or Delete a Connection
It is important to note that editing or deleting a connection can damage your app. Editing a connection field, may corrupt views in the Live App that use the connection. Deleting a connection field will destroy how records are connected across objects and corrupt any views using that connection in the Live App.
Why is My Connection Not Working?
If you are having trouble seeing connected records or choosing connected records from the dropdown, first start by checking the connection field in the object. In the Data section of the Builder, select the object the connection field is on and view that object's records. There, check that the connection field is not blank. While the connection field links the two objects, the field needs to have a selected value in the connection field to link individual records.
You can read more about troubleshooting your connections here.
How to Guides
Once your objects are connected, you can use these connections in powerful ways throughout your application.