All fields have properties, which are set when you create a table or feature class. In ArcGIS, the first properties you set for a field are its name and data type. The other properties you set are dependent on the data type of the field.
You can change certain field properties after you create the table or feature class. For enterprise geodatabases, the properties you can change and how you change them depends on the database management system you use; you can only make changes that your database allows. For example, if your database does not allow you to change the length of a field in a table that contains data, you cannot change the field length through ArcGIS.
You can alter the following field properties:
- Read Only
- Field Name
Certain system fields cannot be renamed. See Define feature class properties for a list of these fields.
- Data Type
You can only change data types if the table is empty. If the table contains data, you cannot change data types.
- Allow or disallow NULL values
If the table or feature class is registered as versioned and its adds table contains data, you cannot change the Allow NULL values property from Yes to No.
- Number Format
- Default Value
If your table or feature class does not contain data, you can increase or decrease this value.
Depending on the data source, not all field properties may be available.
Access field properties from the Fields button on the Data contextual tab. Read more about modifying field properties in fields view.