GIS Geodatabase Design and Management 5 — Questions and Answers
Question 1: What is the effect of setting a feature class to 'archive' in an enterprise geodatabase?
- The feature class is made read-only for all users
- A historical record of all edits over time is maintained, enabling query of past states (Correct answer)
- The feature class is exported to a long-term storage format
- Archiving removes delta table entries older than 30 days
Correct answer: A historical record of all edits over time is maintained, enabling query of past states
Enabling archiving on a feature class causes the geodatabase to maintain a complete change history, allowing users to query the dataset as it existed at any past point in time.
Question 2: In a geodatabase relationship class, what is the 'cardinality' setting used to define?
- The spatial proximity required between related features
- The allowed ratio of origin records to destination records (one-to-one, one-to-many, many-to-many) (Correct answer)
- The attribute field used to join the two classes
- The direction in which messages are sent between related features
Correct answer: The allowed ratio of origin records to destination records (one-to-one, one-to-many, many-to-many)
Cardinality defines whether each origin record can relate to one destination record (1:1), multiple destination records (1:M), or whether many-to-many relationships are allowed (M:N).
Question 3: Which best describes the difference between a 'simple' and a 'composite' geodatabase relationship class?
- Simple relationships allow features to exist independently; composite relationships require destination objects to be owned by the origin (Correct answer)
- Simple relationships require matching primary and foreign keys; composite relationships do not
- Composite relationships only work with point feature classes
- Simple relationships enforce topology while composite relationships enforce attribute domains
Correct answer: Simple relationships allow features to exist independently; composite relationships require destination objects to be owned by the origin
In a simple relationship, both origin and destination objects can exist independently; in a composite relationship, destination objects are owned by the origin and are deleted when the origin is deleted.
Question 4: What is the correct way to add a new spatial reference to an existing feature class in a geodatabase without data loss?
- Delete and recreate the feature class with the new projection
- Use the Project tool to reproject the data into a new feature class with the target spatial reference (Correct answer)
- Modify the feature class spatial reference property directly in ArcCatalog
- Use Define Projection to overwrite the existing spatial reference in place
Correct answer: Use the Project tool to reproject the data into a new feature class with the target spatial reference
The Project geoprocessing tool mathematically transforms coordinates and writes them to a new output feature class with the desired spatial reference, preserving all data.
Question 5: A geodatabase contains a feature dataset. What constraint does this impose on all feature classes added to it?
- All feature classes must have identical attribute schemas
- All feature classes must share the same spatial reference (coordinate system) (Correct answer)
- Feature classes inside cannot participate in topology
- The feature dataset limits each class to a maximum of 1,000 features
Correct answer: All feature classes must share the same spatial reference (coordinate system)
All feature classes within a feature dataset must share the same spatial reference so that topological and network relationships between them can be enforced correctly.
Question 6: Which statement about geodatabase versioning is correct?
- Only one user can edit the default version at a time
- Versions use delta (adds/deletes) tables to track differences from the default version (Correct answer)
- Versioning is supported only in file geodatabases
- Each version stores a full physical copy of all features
Correct answer: Versions use delta (adds/deletes) tables to track differences from the default version
Enterprise geodatabase versioning tracks edits by recording only the added and deleted rows in separate delta tables (A and D tables) rather than copying the entire dataset for each version.
Question 7: What does the 'Compact' operation do to a file geodatabase?
- Removes all topology errors and rebuilds spatial indexes
- Defragments storage by reclaiming space from deleted records and improving performance (Correct answer)
- Merges all feature classes into a single optimized table
- Converts the file geodatabase to an enterprise geodatabase
Correct answer: Defragments storage by reclaiming space from deleted records and improving performance
Compacting a file geodatabase reorganizes internal storage to reclaim space left by deleted records and reduce fragmentation, similar to defragmenting a file system.
GIS Geodatabase Design and Management 5
What is the effect of setting a feature class to 'archive' in an enterprise geodatabase?