Computer Knowledge
Database Management Systems
5,344 Questions
Database Management Systems (DBMS) form the core framework for data storage, retrieval, and security in modern software applications. Concepts such as the E-R model, backup planning, SQL integration, and big data architecture are essential for computer knowledge sections. This hub offers a comprehensive set of practice questions to master DBMS fundamentals and advanced database operations.
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Database Management Systems Questions
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a. Partition by Key
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b. Partition by Round Robin
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c. Partition by Expression
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d. Partition by Range
B
Correct answer
Explanation
Partition by Round Robin distributes records evenly across partitions by cycling through partitions sequentially - first record to partition 1, second to partition 2, and so on, then back to partition 1. This ensures balanced distribution regardless of data characteristics. Key partitioning causes skew if keys aren't uniformly distributed, Expression partitioning depends on the expression logic, and Range partitioning creates ordered but potentially uneven partitions.
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- Insert into
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- Create mining structure
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- Browse data
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- Select from
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- Browse mining model
D
Correct answer
Explanation
DMX (Data Mining Extensions) uses SELECT FROM syntax for browsing and prediction queries against mining models. This allows you to retrieve patterns and make predictions from trained models. The other options like INSERT INTO, CREATE MINING STRUCTURE are for different operations (training, creation).
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- Many dimensions, large dense datasets
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- Few dimensions, small dense datasets
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- Few dimensions, small sparse datasets
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- Many dimensions, small sparse datasets
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- Many dimensions, large sparse datasets
B
Correct answer
Explanation
Relational OLAP (ROLAP) stores data in relational databases and is most suitable when you have few dimensions and small dense datasets. ROLAP avoids the preprocessing overhead of MOLAP and works well when data doesn't have significant sparsity. For many dimensions or large datasets, MOLAP or HOLAP would be more appropriate.
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- Comprehensive data on operations from all departments
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- A subset of a data warehouse
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- Individual invoices
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- Accounting profit and loss reports
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- Data managed by a particular department of the company
B
Correct answer
Explanation
A dependent data mart is derived from and dependent on the enterprise data warehouse. It contains a subset of the data warehouse focused on a specific business unit or function. Independent data marts pull directly from source systems, but dependent ones are subsets of the centralized warehouse.
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- Data fields that reference numeric data should be indexed.
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- Only data fields that change over time should be indexed.
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- Data fields that are referenced by queries should be indexed.
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- All data fields should be indexed.
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- Data fields that reference text and large object data should be indexed.
C
Correct answer
Explanation
In a data warehouse, indexing should be applied to columns and data fields that are frequently referenced by queries to speed up data retrieval performance. Indexing every field or only fields changing over time would be inefficient and impractical.
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- Data about an organization's staff
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- Data about accounting entries
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- Data about an organization's structure
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- Data about an organization's products
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- Data about transaction activity
E
Correct answer
Explanation
Transaction activity records individual business events continuously in real-time, making it the most dynamic and frequently changing type of data. Product catalogs, organizational staff, and structural data are structural and change much less frequently.
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- Capture and store data rules.
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- Generate programs to extract data from a source system.
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- Store data warehouse database designs.
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- Store the layout or design of the load files.
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- Generate programs to transform data.
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- Database backups
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- Time an uncommon query will take
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- People entering data into the source database
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- Number of tables in the data mart, so they do not exceed six tables
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- Requirements of the department that will use the data mart
E
Correct answer
Explanation
Data mart design must begin with understanding the business requirements of the department that will use it. This determines what data to include, how to structure it, what metrics to calculate, and how to present the information. Database backups, query performance, data entry processes, and table counts are implementation or operational details that come after defining requirements.
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It loads the Java code into the database.
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It publishes Java methods in CardValidation.java
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It loads the metadata related to the Java class file into the database.
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It loads the Java class file into the Java pool in the database instance.
A
Correct answer
Explanation
The loadjava utility loads Java source code, class files, and resources into an Oracle database. When given a .java file, it compiles and loads the Java code into the database schema. It does not publish methods (that requires separate publication) nor does it specifically load metadata only into Java pool.
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Query results are bigger than the available space in the result cache are not cached
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Query results are stored even when you explicitly use the /*+ no_result_cache */ hint in query.
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All query results are stored in the result cache if possible.
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Query results are stored only when you explicitly use the /*+ result_cache */ hint in your query
C
Correct answer
Explanation
RESULT_CACHE_MODE=FORCE forces all query results to be cached if possible, ignoring the /*+ no_result_cache */ hint. The FORCE setting means caching happens regardless of explicit hints. Results are cached when they fit in available cache space, but hints that disable caching are overridden.
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They can be used as attributes of a user-defined data type.
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They cannot use redo logging.
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They cannot be passed as parameters to PL/SQL subprograms.
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They can be stored in a tablespace that is different from the tablespace that stores the table containing the LOB column
A,D
Correct answer
Explanation
Internal LOBs can be used as attributes within user-defined data types (object types), allowing structured data with large object components. They also support separate tablespace storage from their parent table for better management. They DO use redo logging (contrary to option B) and CAN be passed as parameters to PL/SQL subprograms (contrary to option C).
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SecureFiles storage can be used for internal and external LOBs
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ASSM must be enabled for a tablespace to store SecureFile LOBs
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SecureFile is the default storeage paradigm for all LOBs
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SecureFile options enabled for a LOB column can be overridden on a per-LOB basis wihtin the LOB column
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DDL report for all objects dependent on a table
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DDL report for all the invalidated objects in a schema
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data definition language (DDL) report for all the tables in a schema
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DDL report for all the objects stored in a tablespace
A,C
Correct answer
Explanation
DBMS_METADATA package provides GET_DEPENDENT_DDL to retrieve DDL for all objects that depend on a specified object (like a table). GET_DDL can fetch DDL for objects of a specific type within a schema, such as all tables. It doesn't directly track object invalidation status (B is false) or provide tablespace-level object listings (D is false).
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Application server
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Web server
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Batch server
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Browser Cache
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None of these
A
Correct answer
Explanation
When an Application Engine program is loaded into memory in PeopleSoft, the physical tables that the program will operate on are locked to prevent concurrent modifications. This ensures data integrity during program execution and prevents conflicts from other processes.