You can tweak the schema generated by AppSheet, but please do so carefully!
In the Data > Columns tab of the app editor, you'll see the column structure AppSheet has deduced for your data. This isn't always what you want. The best way to change it is to change your spreadsheet, but if that isn't possible, you may also decide to change the schema directly. These changes can include:
Name: The name the app uses to refer to the column. The column name should match the column's name in the underlying data source (e.g., the column header in the spreadsheet).
Type: The type of data contained in the values of the column. The choice of data type affects the behavior of this field in the app. For example, you might want a particular text column to be a
LongText, or a particular image column to be a
App formula: App formulas are expressions that are automatically computed in the app to populate the value of a column. This is not to be confused with spreadsheet formulas, which are computed in and by the spreadsheet itself. If a column has an app formula, the user of the app cannot provide a value to override the formula.
Key: A key column value uniquely identifies the row within the table, and should be chosen with care. Only one column of a table can be the table's key column.
Show?, Editable?, and Require?: Use Show? to display or hide the column value; Editable? to allow or prevent the user from modifying the column's value; and Require? to require the user supply a column value or optionally leave the value blank.
Description: The description, if provided, is shown to the user instead of the column name in form views. It is automatically populated from notes on the column header cells in the spreadsheet.
Initial Value: When a new entry is created in the app, the fields are populated with default values that are typically constants, but can be any supported expression that matches the expected column type. If an expression, it is recomputed until the user of the app explicitly provides a value.
Search: Indicates the data values in the column can be searched using the Search button in the app. By default, Search is enabled for most textual columns, but is not enabled for columns containing non-textual values. You can modify the Search attribute to control which columns are searchable. Search is text-based. It is both case-insensitive and diacritic-insensitive. Search is performed against the entire table, including column data values that aren't currently displayed on screen.
Scannable: Indicates a column can be filled by scanning a barcode or QRCode. By default, no column is scannable unless explicitly indicated.
Sheet Formula: Indicates a formula on the spreadsheet that is calculated (and the result shown in the app) once the user hits "Save" (or "Sync" if the app is set to "Delayed Sync").