Columns: The Essentials

Once you have tables in the editor, you can categorize each column, and set properties to define their roles and behaviors.

• About columns
• View and edit columns

About columns

The following sections introduce you to columns and the :

• Column structure
• Column basics: Name and data type
• Keys
• Column properties: Roles and behaviors
• Column order
• Row labels
• Virtual columns

Column structure

As you determine all your tables, you'll review each column's type and properties and make changes to them within app the editor, relate different tables to one another, and more. See View and edit columns.

Column basics: Name and data type

You start defining your column when you give it a name in your spreadsheet and populate it with data of a particular type. The column type determines the role of the column in the app. 

Each column has a name. The editor determines the name of your column based on the top cell in the spreadsheet of each column. The editor deduces the type of data you have in your column based on the data in it.

For example, if you have a column named Birthday and all of your data points use the format 03-20-2000, AppSheet will assume the column is of type Date.

The editor often correctly identifies the data type, but when it doesn't, you can change it using the Type drop-down.

This capability is useful for advanced scenarios where the data comes from non-spreadsheet sources. Another case where the column type may be different is that of the App column type, which is used to navigate to different views or apps. However, if you're just getting started, using the default types should work pretty well.

There should rarely be a reason to change the column name. If the column name in the editor isn't the same as the column header name in your spreadsheet, errors will occur.

If there's a mismatch between columns in the app editor and the spreadsheet data, you'll get an error that means you need to regenerate the table.

Keys

Keys uniquely identify each row from other rows using a particular column.

The key may be a single column (such as Employee ID) or two or more columns (such as FirstName and LastName). Each row in the table must have a key value that uniquely identifies it. In other words, no two rows in a table may have identical key values. This is critical, because it allows AppSheet to reliably find the right table row.

When a user changes data in the app, they're making changes to a local copy of the data cached on the device. When the user syncs these changes to the server, AppSheet sends the updated data to the server, finds the updated row using its unique key value, and applies those changes to that row. AppSheet can only find the right row because each row has a unique key value.

There are several ways keys can be determined. They can be natural or computed depending on the case.

Column properties: Roles and behaviors

Column settings enable you to modify roles and behaviors. Roles determine what a column is, behaviors determine what a column does. There are several settings you can change for the role and the behavior of a column which enables you to customize your column so it functions exactly as you want. See Configure column properties. 

To control other aspects of columns, such as their order, see UX: The Essentials.

Column order

AppSheet does its best to automatically order columns in order of importance. If you’re using the Tabular or Grouped List views or the Table view, you can manually control column order.

To understand how AppSheet automatically orders columns and to manually control column order, see Control column order.

You can decide which column is the key column. Sometimes, the editor will give you an automatically computed key if there's no obvious unique identifier. You can learn more about keys in What is a Key?

Row labels

Row labels allow you to choose the most important columns in a table. One image column and one non-image column can be used as labels. All tables have a non-image label. The row labels are used to display references to rows in other tables.

Virtual columns

A virtual column is a column of a table in the app that doesn't have an actual column in the underlying spreadsheet. Instead, it's automatically computed via an app formula expression.

Sometimes, virtual columns are system-generated and you'll see them show up in your column structure. For example, you can use virtual columns to create Row Labels, allowing you to identify columns that are the most important in a table.

For more information, see:

• Use virtual columns
• Improve the presentation of detail and form views using Show types

View and edit columns

To view and edit the columns in a table:

1. Open the app in the editor.
2. Go to Data  and select the table you want to view or edit in the list.
   We've made some improvements to the app editor.
   You are opted in to the new editor by default, but you can switch back to the legacy editor at any time.
    

   If you are using the legacy editor

   Go to Data > Columns and expand the table you want to view or edit.
3. Edit any of the column properties displayed.
4. Click Edit  to view the full set of properties for a specific column. See Configure column properties for more information about the properties that you can configure.
5.  Save the app by selecting one of the following:
   • Save - Save the app.
   • Save & verify data - Save the app and verify that it is runnable based on external dependencies.

You also have the option to add virtual columns 

If you make changes to the structure of the columns in your spreadsheet, you need to regenerate the table. This ensures the editor will take in the new data you've added to your spreadsheet without running into errors.