Modify field properties in ArcMap

Summary

All table fields have properties, which are set when a table or feature class is created. In ArcGIS, the first properties to set for a field are its name and data type. The other properties are dependent upon the data type of the field.

Some field properties can be changed after the table or feature class is created. For enterprise geodatabases, the properties that can be changed and how they can be changed depends on the database management system in use; only changes can be made that the database allows. For example, if a database does not allow changing the length of a field in a table that contains data, you cannot change the field length through ArcGIS.

Field properties that can be altered are as follows:

• Field Name: Certain system fields cannot be renamed. See Defining feature class properties for a list of these fields.
• Data Type: If the field contains data, you cannot change data types that would lead to loss of data. For example, you cannot change a long integer or float to a short integer, or change a BLOB to text.
• Alias
• Allow or disallow NULL values: If the table or feature class is registered as versioned, you cannot change the Allow NULL values property from Yes to No.
• Default Value
• Domain
• Length: If the table or feature class does not contain data, you can increase or decrease this value. If the table or feature class contains data, you can only increase the field length.

Procedure

Field properties are accessed from the Fields tab of the Table Properties or Feature Class Properties dialog box.

Follow these steps to modify existing field properties:

1. Start ArcMap or ArcCatalog and connect to the geodatabase containing the table or feature class to modify field properties.

   If the table or feature class is in an enterprise, workgroup, or desktop geodatabase, it is necessary to connect as the table owner to modify field properties.

2. Right-click the table or feature class and click Properties.
3. Click the Fields tab.
4. Choose the field to modify from the Field Name list.
   • To rename the field, click the text of the name and type a new name.
   • To change the data type, choose a new type from the corresponding Data Type drop-down list.
   • To change the alias, default value, or length of a field, double-click the value in the Field Properties list and type a new value.
   • To change the null value or associated domain for a field, choose a new value from the drop-down list.
5. When all the modifications are finished, click OK to close the Table Properties or Feature Class Properties dialog box and apply the changes.