A geodatabase stores geographic data organized in datasets. A geodatabase can maintain both spatial and nonspatial data. Examples of the types of datasets that might be maintained in a geodatabase include object and feature classes, relationship classes, topologies, networks, terrains, raster datasets, and raster catalogs. An ArcSDE geodatabase stores data in a relational database and utilizes the capabilities of the relational database to support storage of large datasets and provide efficient multiuser access to data.
A typical life cycle for an ArcSDE geodatabase involves the following steps:
- Geodatabase design
- Geodatabase creation
- Initial data loading
During this phase, data is loaded for an area of interest. The data being loaded can come from existing corporate databases or map libraries, or it can be purchased.
- Editing and data maintenance
During this phase, existing data is modified, and new data is added to the database as required. Edits are made against the database corresponding to application-defined units of work or transactions such as the addition of a new sewer or an update to a parcel boundary. The editing and data maintenance phase can also include incremental data loading, which further expands the boundaries of the database. Such incremental data loading may occur when a company acquires new territories or when the spatial extent of a study area expands.
Examples of changes that might be made to a geodatabase during editing and data maintenance include the following:
- Updating the address of a customer in a utility database
- Subdividing a parcel to reflect a sale in a cadastral database
- Adding a service to a new customer in a utility database
- Updating a forest block to reflect a planned cutting operation
- Designing a new substation in a utility database
- Checking out a section of a utility database, modifying it in the field to reflect storm-related damage, and checking the work back in to the central database
- Planning a new subdivision in a land planning database
- Performing a what-if scenario for a disaster recovery simulation
Each of the above changes corresponds to an application-defined unit of work or transaction that is performed against a geodatabase.
The topic Data maintenance strategies discusses how you can support transactions of varying complexity and duration against both simple and complex geographic data.