Table field types

When you create a relationship between two tables, the key fields on which the relationship is based must store data of the same type. For example, if you want to relate two tables, the key fields must both be defined as short integer or one of the other supported types.

These tables both have a text field that stores the same data; the tables can be related using these fields as the key fields.

Not all field types can be used to create relationships. Supported field formats are short integer, long integer, float, double, text, and object ID.

Reminder: Geodatabase field types

The geodatabase supports the following field types for user-defined attributes in feature class tables and nonspatial tables.

Name	Specific Range, Length, or Format	Size (bytes)	Applications
Short integer	-32,768 to 32,767	2	Numbers without fractions within specific range; coded values
Long integer	-2,147,483,648 to 2,147,483,647	4	Numbers without fractions within specific range
Single-precision floating point number (Float)	Approx. -3.4E^38 to 1.2E^38	4	Numbers with fractions within specific range
Double-precision floating point number (Double)	Approx. -2.2E^308 to 1.8E^308	8	Numbers with fractions within specific range
Text	Up to 64,000 characters	Varies	Names or other textual qualities
Date	mm/dd/yyyy hh:mm:ss AM/PM	8	Date and/or time
BLOB	Varies	Varies	Images or other multimedia
Raster	Varies	Varies	Images or pictures
GUID	36 characters enclosed in curly brackets	16 or 38	Customized applications requiring global identifiers