You define the properties of a table or feature class when you create it in a database or geodatabase. You can use the New Table or New Feature Class wizards from the database connection in the Catalog tree to do this. Both these wizards are accessed by right-clicking a database connection (or feature dataset in a geodatabase), pointing to New, and clicking either Feature Class or Table.
The properties you define using the wizards are shown in the following table. The check marks indicate to which object—a table or a feature class (spatial tables)—a property applies.
| Property | Table | Feature class |
|---|---|---|
Name and alias |
Aliases can be set only in geodatabases. |
Aliases can be set only in geodatabases. |
Feature type |
| |
Spatial type |
Databases only | |
Geometry properties, including the following:
|
X,y tolerance is set only in geodatabases. | |
Reference scale and map units |
Applies to dimension and annotation feature classes in geodatabases only. | |
Applies to annotation feature classes in geodatabases only. | ||
Applies to annotation feature classes in geodatabases only. | ||
Applies to dimension feature classes in geodatabases only. | ||
Geodatabases only |
Geodatabases only | |
Field name, data type, and length |
|
|
Names, aliases, feature types, and spatial properties are discussed in the sections below. For information on the other properties, follow the links in the table.
Table and feature class names
When you create a table, give it a name that indicates what data the table stores. Table names must be unique in a geodatabase—you can't have more than one table with the same name.
When you create a table or feature class in an enterprise geodatabase or database, the name of the schema in which the table is stored is appended to the table or feature class name. In all databases other than Oracle, the name of the database is also appended to the table or feature class name. This is referred to as the fully qualified table name. For example, if user Werther creates a table named alpacas in a Microsoft SQL Server database named spdata, the fully qualified name of the table is spdata.werther.alpacas.
It is possible for other users to create tables named alpacas because the tables they create will have their user names appended to the table names. For example, if user Gretchen creates her own alpacas table, the name in the database is spdata.gretchen.alpacas.
However, it is recommended that you not reuse table names even if they are stored in different schemas or databases. In this example, if both tables contain information about alpacas, there is no reason to have two separate tables. If the data is distinctly different between the two tables, the table names should reflect that.
Renaming fields
You can rename fields in a table or feature class on the Fields tab on the Properties dialog box. Fields in a geodatabase from the ArcGIS 10 release and later support renaming, and fields in database tables can be renamed.
To rename a field, right-click the feature class or table in the Catalog tree and click Properties. Click the Fields tab to see a list of fields in that table or feature class. Click the text of the field you want to rename and type a new name. Click OK to apply your changes and close the Properties dialog box.
The following fields cannot be renamed:
- ObjectID and globalID fields
- Any shape-related field; Shape, shape length, shape area
- The enabled, ancillary role or network weight fields of a network feature class
- Representation fields
- Fields in a feature class participating in a network dataset, terrain, or parcel fabric
- Fields used for editor tracking
- Relationship class primary key and foreign key fields
- The subtype field
- Raster fields
Field name rules and limitations
The following table lists supported field name character rules:
| Character | Start of name | Other position | In alias |
|---|---|---|---|
Letters (A-Z) |  | | |
Underscore ( _ ) | | | |
Digits (0-9) | | | |
Spaces | | ||
Symbols (other than underscore) | | ||
Superscript letters and digits | | ||
Subscript letters and digits | |
Additional field name rules and limitations are as follows:
- Field names cannot contain reserved words, such as all or result.
Consult your database management system (DBMS) documentation for additional reserved words.
- The length of field (column) names depends on the underlying database.
See file geodatabase size and name limits or database data and ArcGIS for more information about database-specific limitations.
Aliases
When you create a table or feature class in a geodatabase, you can assign an alias to it. An alias is an alternate name. If you assign an alias to a table or feature class, that is the name users see when they add it to ArcMap. Users can still look up the name of the table or feature class by going to the Source tab on the Layer Properties dialog box.
Feature types
Feature types are only defined for feature classes and are defined at the time of feature class creation. They specify which type of geometry will be stored in the feature class.
Choose a feature type that best represents the real-world object you are trying to symbolize on your maps. This may vary depending on the map scale with which you use the feature class. Also consider the type of analyses you may want to perform with the data.
The following table contains a list of the types of features you can specify for a feature class, along with descriptions of typical objects or concepts represented with that feature type. A third column contains notes on the type of analyses or relationships you can create or perform with only this feature type.
| Feature type | Real-world object or concept | Unique spatial analyses or relationships |
|---|---|---|
Polygons | Objects or places that have area, such as water bodies, jurisdictional or service area boundaries, wildlife ranges, or flood zones |
|
Lines | Linear objects, such as rivers, streets and highways, utility lines, or survey transects |
|
Points | A narrowly localized position or spot, such as a survey marker, sample point, telephone pole, or individual plant |
|
Multipoints (Geodatabase feature classes only) | An object or place that is composed of multiple localized positions having the same attributes, for instance, a stand of the same species of tree, an island chain, multiple buildings in the same office complex, or lidar or sonar point clusters | |
Multipatches (Geodatabase feature classes only) | Three-dimensional features, such as buildings, mountains, water tables, and planets |
|
Annotation (Geodatabase feature classes only) | Place or object names or identifiers, such as street names, hydrant ID numbers, land values, or elevation |
|
Dimensions (Geodatabase feature classes only) | Measurements, such as distances, lengths, widths, and depths |
|
You may need to have feature classes of different feature types represent the same data. For example, if you usually create maps at a scale at which it makes sense to use a polygon feature class to represent city parks (approximately 1:25,000 to 1:100,000) but you sometimes need to create maps at a scale at which you need the parks to be shown as points (approximately 1:250,000 to 1:500,000), you can create a second parks feature class that uses centroid points to represent the location of the parks.
Or you may need data represented in one feature type (for mapping purposes), but you need the same data represented in a different feature type to perform certain analyses. For example, you have a river feature class that stores the rivers as lines. This works fine for modeling flow or analyzing where rivers cross other features, but to perform any sort of area analysis, such as clipping or calculating the area of your soils polygon feature class that is covered by rivers, you also need to model your rivers as polygon features so they have area and not just length.
Spatial properties
Tables that store spatial data, such as those that make up feature classes, have properties that define where the data is located in space:
- X,y coordinates—The data's location in two-dimensional space.
- Z-coordinates—The data's location in the third dimension.
- M-coordinates—Measures that can be used to calculate distances along line features.
For an explanation of x-, y-, z-, and m-coordinates, see Feature class basics.
- A spatial reference—Includes a coordinate system; x-, y-, z-, and m-tolerance values; and x-, y-, z-, and m-resolution.
For details on spatial references, see the Spatial references.
Together, these properties allow you to find the location of a given feature on the earth.