A linked relation column (formerly known as a reverse lookup column) serves as a complement to the relation column type, which allows you to pull in information from another table. Linked relations represent a bi-directional relationship between data in different tables and allow you to edit values from either side of the connection.
Linked relations are a very powerful, useful tool in Coda. They make it easier to connect and summarize data in related tables - such as Projects and Tasks. Once you get the hang of them, you might find yourself using linked relations all over your Coda docs!
Within this article you’ll find...
Create a linked relation
To create a linked relation column, you first need to create a relation column (read all about those here).
For instance, let’s say you have two tables: a Tasks table and a Projects table. You’ve added a relation column to your Tasks table, which references the Projects table. For each row in the Tasks table, you use that relation column to indicate which Project goes with each task.
But now, you want to know which tasks are associated with each Project. In other words, you want to add a linked relation column to your Projects table. No problem - you can do this in a few clicks:
Click on the + icon in the upper right corner of your table to add a column.
In our example, you’ll be adding this column to the Projects table.
From the list of column types, choose Linked relations.
You’ll then see a list of all other tables (and columns) that reference this current table. Select which relation column you want to utilize from the list.
In our example, you’ll want to look for the Tasks (Project column) option.
That’s it! Your linked relation column has been added.
You’ll see that this newly created linked relation column automatically contains the data you’d expect to see - based on what you’ve added to the original relation column.
💡Tip: You can also add linked relation columns via the original relation column. Just go to the relation column in your Tasks table, right click on the column header, and find the Create linked relation column on Projects button. Click this and notice how that linked relation table is conveniently added to your Projects table.
Explore the linked relation formula
Behind each linked relation column is a formula. This formula is automatically built when you create a linked relation column, so there’s no need to write or edit yourself. But if you’re curious, you can explore the formula by right clicking on the column header, then selecting Edit formula.
You’ll see there that linked relation columns are really just filter formulas. The formula takes the referenced table, and filters it to only show rows that contain references to the current row in your table. You can even click around on the various components of the formula, and the formula builder will provide some info to help you understand each piece. If you’re curious about Coda formulas, check out this article.
Linked relation options
Just like all columns in Coda, the linked relation column has a number of settings that you can adjust based on your needs. To view these, right click on the column header, then select Linked relation options.
Here you’ll find:
Allow two-way edits. This important feature lets you decide whether the contents of your linked relation column can be manually changed. By default, this setting will be toggled on when you first create a column. Read more about two-way editing below.
Allow multiple selections. Toggle this setting off if you’d like to limit your linked relation to one item (row reference) per cell. For example, you may want a Task to be part of only one Project. Note that this setting is toggled on by default.
Turn off two-way editing
When two-way editing is turned on for linked relation columns, this allows for a bidirectional relationship between the two linked tables. In other words, when this setting is on, you can make a change directly to the contents of the linked relation column, and this will automatically trigger a corresponding change to the original relation column.
By default, all new linked relation columns are created with this setting turned on. But sometimes you may want to only see the values from the source table - without the ability to edit them directly via the linked relation column. In that case, just head to the column settings and switch off the Allow two-way edits toggle.
Add related columns
Linked relation columns contain row references. The value of the display column is what’s shown. But when you hover over an item in a linked relation column you’ll see the full contents of the row, including the other columns. So what if you want to pull in one of these specific columns - something other than the display column - and show that in your table? No problem!
To do this, just follow these steps:
Right click on the header of your linked relation columns
From the drop-down menu, select Add related column
You’ll then see a list of all the columns in that other table. Choose which column you’d like to add.
That’s it! That new column will now automatically populate based on which items are contained in the linked relation column for each row.
Is a linked relation the same as a reverse lookup?
Yes - we recently updated the name of this feature to “linked relation.” With the rename, we also released a suite of improvements to make using this valuable feature even easier.
Can I use a linked relation column without a relation column?
No - linked relation columns are a compliment to relation columns. You need to first create a relation column on one table, and then can create a linked relation column on the other table.
What type of data do linked relation columns contain?
Linked relation columns contain row references. While they may look like they just contain text, the data is actually much richer. Each “bubble” (or “chip,” as we sometimes call it) within a linked relation column represents a row from another table. If you hover over the bubble, you’ll see a pop-up with the full contents of that row, including all the columns it contains.
Can I pull data from only one specific column into my linked relation column?
Yes! The easiest way to do this is to use the linked relation column to add a related column. Check out the Add related columns section on this above.
What’s the difference between a relation and a linked relation?
A relation column represents the primary connection from Table A to Table B, whereas a linked relation represents the other side of the connection on Table B - and even lets you edit values back in Table A.
Another way to think of it: one relation column can have many linked relation columns connected to it, while a linked relation column is only connected to one relation column.