Limits on the size of database objects in an enterprise geodatabase are mostly dependent on hardware limitations. The limit on database object name size is the smaller of either the limit enforced by the database management system (DBMS) or the geodatabase limit. Limits vary from one database management system to the next. The types of characters allowed in object names vary by database management system but are also affected by how ArcGIS stores and queries the object information.
Size limits
Most size limits in a database depend on the database management system edition and hardware limitations. One exception is the number of fields (columns) supported in a table or feature class; the maximum number is 500. Be aware, though, that depending on the data types you define for the columns, the maximum number of columns in a table could be less than 500. Most database vendors do not recommend creating tables with over 200 columns of any data type.
Number of characters in object names
For most object names, ArcGIS clients use whatever character limits the underlying database management system imposes.
The exceptions are listed in the following table. The number of characters listed assumes the use of ANSI text. UTF-8 characters use at least twice as many bytes as ANSI characters, thereby reducing the number of allowed characters.
| Db2 | Informix | Oracle | PostgreSQL | SQL Server | |
|---|---|---|---|---|---|
Field (column) name | 31 | 31 | 30 | 31 | 31 |
Password | 31 | 31 | 31 | 31 | 31 |
Geodatabase table or feature class alias | 255 | 255 | 255 | 255 | 255 |
User or role name | 30 | 31 | 30 | 31 | 31 |
Version name | 62 | 62 | 62 | 62 | 62 |
Character type limits in object names
Database management systems have different definitions of acceptable characters for object names. Most names must begin with a letter and cannot contain spaces, backslashes, or reserved database management system keywords. Some databases allow special characters such as forward slashes (/), underscores (_), dollar signs ($), dashes (-), dots (.), or mixed cases. Sometimes the database allows you to use special characters or reserved keywords, or force mixed, upper-, or lowercase names if you provide the object name enclosed in delimiters, such as double quotation marks.
However, ArcGIS does not delimit object names. Do not create any tables, feature classes, indexes, databases, users*, roles, or other object names that require delimiters if you will be using them with ArcGIS. The object will be created in the database, but you cannot access it from ArcGIS.
*SQL Server user names containing special characters are delimited to fully support Active Directory Groups and Windows Authenticated logins; however, ArcGIS does not support user names containing single quotation marks or apostrophes.