There are three types of geodatabases:
- File geodatabases—Stored as folders in a file system. Each dataset is held as a file that can scale up to 1 TB in size. The file geodatabase is recommended over personal geodatabases.
- Personal geodatabases—All datasets are stored within a Microsoft Access data file, which is limited in size to 2 GB.
- Enterprise geodatabases—Also known as multiuser geodatabases, they can be unlimited in size and numbers of users. Stored in a relational database using Oracle, Microsoft SQL Server, IBM Db2, IBM Informix, or PostgreSQL.
Comparing the three types of geodatabases
| Key characteristics | Enterprise geodatabase | File geodatabase | Personal geodatabase |
|---|---|---|---|
Description | A collection of various types of GIS datasets held as tables in a relational database (This is the recommended native data format for ArcGIS stored and managed in a relational database.) | A collection of various types of GIS datasets held in a file system folder. (This is the recommended native data format for ArcGIS stored and managed in a file system folder.) | Original data format for ArcGIS geodatabases stored and managed in Microsoft Access data files.(This is limited in size and tied to the Windows operating system.) |
Number of users | Multiuser: many readers and many writers | Single user and small workgroups: many readers or one writer per feature dataset, stand-alone feature class, or table. Concurrent use of any specific file eventually degrades for large numbers of readers. | Single user and small workgroups with smaller datasets: some readers and one writer. Concurrent use eventually degrades for large numbers of readers. |
Storage format |
| Each dataset is a separate file on disk. A file geodatabase is a file folder that holds its dataset files. | All the contents in each personal geodatabase are held in a single Microsoft Access file (.mdb). |
Size limits | Up to DBMS limits | One TB for each dataset. Each file geodatabase can hold many datasets. The 1 TB limit can be raised to 256 TB for extremely large image datasets. Each feature class can scale up to hundreds of millions of vector features per dataset. | Two GB per Microsoft Access database. The effective limit before performance degrades is typically between 250 and 500 MB per Microsoft Access database file. |
Versioning support | Fully supported across all DBMSs; includes cross-database replication, updates using checkout and check-in, and historical archiving | Only supported as a geodatabase for clients who post updates using checkout and check-in and as a client to which updates can be sent using one-way replication. | Only supported as a geodatabase for clients who post updates using checkout and check-in and as a client to which updates can be sent using one-way replication. |
Platforms | Windows, UNIX, Linux, and direct connections to DBMSs that can potentially run on any platform on the user's local network | Cross-platform. | Windows only. |
Security and permissions | Provided by DBMS | Operating file system security. | Windows file system security. |
Database administration tools | Full DBMS functions for backup, recovery, replication, SQL support, security, and so on | File system management. | Windows file system management. |
Learn about creating geodatabases
File geodatabases and personal geodatabases
File and personal geodatabases, which are freely available to all users of ArcGIS Desktop Basic, Desktop Standard, and Desktop Advanced, are designed to support the full information model of the geodatabase, which comprises topologies, raster catalogs, network datasets, terrain datasets, address locators, and so on. File and personal geodatabases are designed to be edited by a single user and do not support geodatabase versioning. With a file geodatabase, it is possible to have more than one editor at the same time provided they are editing in different feature datasets, stand-alone feature classes, or tables.
The file geodatabase was a new geodatabase type released in ArcGIS 9.2. Its goals are to do the following:
- Provide a widely available, simple, and scalable geodatabase solution for all users.
- Provide a portable geodatabase that works across operating systems.
- Scale up to handle very large datasets.
- Provide excellent performance and scalability, for example, to support individual datasets containing well over 300 million features and datasets that can scale beyond 500 GB per file with very fast performance.
- Use an efficient data structure that is optimized for performance and storage. File geodatabases use about one-third of the feature geometry storage required by shapefiles and personal geodatabases. File geodatabases also allow users to compress vector data to a read-only format to reduce storage requirements even further.
- Outperform shapefiles for operations involving attributes and scale the data size limits way beyond shapefile limits.
Personal geodatabases have been used in ArcGIS since their initial release in version 8.0 and have used the Microsoft Access data file structure (the .mdb file). They support geodatabases that are limited in size to 2 GB or less. However, the effective database size is smaller, somewhere between 250 and 500 MB, before the database performance starts to slow down. Personal geodatabases are also only supported on the Microsoft Windows operating system. Users like the table operations they can perform using Microsoft Access on personal geodatabases. Many users really like the text-handling capabilities in Microsoft Access for working with attribute values.
ArcGIS will continue to support personal geodatabases for numerous purposes. However, in most cases, Esri recommends using file geodatabases for their scalability in size, significantly faster performance, and cross-platform use. The file geodatabase is ideal for working with file-based datasets for GIS projects, personal use, and in small workgroups. It has strong performance and scales well to hold extremely large data volumes without requiring the use of a DBMS. Plus, it is portable across operating systems.
Typically, users will employ multiple file or personal geodatabases for their data collections and access these simultaneously for their GIS work.
Enterprise geodatabases
When you need a large, multiuser geodatabase that can be edited and used simultaneously by many users, the enterprise geodatabase provides a good solution. It adds the ability to manage a shared, multiuser geodatabase as well as support for a number of critical version-based GIS workflows. The ability to leverage your organization's enterprise relational databases is a key advantage of the enterprise geodatabase.
Enterprise geodatabases work with a variety of DBMS storage models (Oracle, Microsoft SQL Server, PostgreSQL, IBM Db2, or IBM Informix). Enterprise geodatabases are primarily used in a wide range of individual, workgroup, department, and enterprise settings. They take full advantage of underlying DBMS architectures to support the following:
- Extremely large, continuous GIS databases
- Many simultaneous users
- Long transactions and versioned workflows
- Relational database support for GIS data management (providing the benefits of a relational database for scalability, reliability, security, backup, integrity, and so forth)
- SQL types for Spatial in all supported DBMSs (Oracle, Microsoft SQL Server, PostgreSQL, IBM Db2, or IBM Informix)
- High performance that can scale to a very large number of users
Through many large geodatabase implementations, it has been found that DBMSs are efficient at moving in and out of tables the type of large binary objects required for GIS data. In addition, GIS database sizes can be much larger and the number of supported users greater than with file-based GIS datasets.
For information about the enterprise geodatabase architecture and how enterprise geodatabases leverage relational database technology, see Architecture of the geodatabase.