Database Management Systems: Advantages, Models, and Key Concepts

1. Know the disadvantages and advantages of DBMS.

Advantages: centralized integrated view; reduced redundancy/anomalies; improved sharing/concurrency; centralized security, integrity, backup/recovery; metadata and ad‑hoc SQL queries. Disadvantages: higher cost; administrative complexity; need for skilled DBAs; vendor dependence; possible performance overhead.

1-3a Role and Advantages of DBMS

Role: intermediary that manages database structures, access, transactions, integrity, security, and metadata; provides query/transaction services and an integrated view of data.

2. What is the column's range of permissible values called?

Domain.

3. What is the row's range of permissible values called?

A row (tuple) must conform to each column's domains and the table's integrity constraints; no separate global name beyond tuple validity by attribute domains.

4. What is the practical significance of taking the logical view of a database?

It abstracts physical storage so designers/users work with logical tables/relationships, simplifying design and separating logical requirements from physical implementation.

5. What is a data warehouse (definition, abilities, structure use, etc.)?

A centralized repository for integrated, historical data from many sources optimized for decision support/OLAP and large‑scale analytics; structures favor query/report performance (may use normalized or denormalized designs).

6. What are the advantages and disadvantages of database systems compared to its predecessor?

Advantages vs file systems: centralized control, reduced redundancy, stronger integrity/security, easier sharing, ad‑hoc queries, metadata. Disadvantages: higher cost, complexity, need for DBAs, migration issues, potential join/performance overhead.

7. What is a field?

A named data element (character or group of characters) that stores a single piece of information in a record (maps to a column).

8. What are standards in terms of database administration?

Documented conventions, naming rules, policies, procedures, and controls ensuring consistent design, security, performance, and operations across the DB environment.

9. What is normalization?

Process of decomposing table structures to minimize redundancy and eliminate insertion/update/deletion anomalies by applying normal forms (1NF, 2NF, 3NF, BCNF, 4NF).

10. What is an issue that arises if different versions of the same data appears in different places?

Data inconsistency causing integrity problems and update/insert/delete anomalies.

11. What is a DBMS and its functions?

DBMS: software that creates/manages databases. Functions: storage/retrieval, transaction/concurrency control, integrity enforcement, security/authorization, backup/recovery, indexing/performance tuning, query processing (SQL), metadata management.

12. What is Metadata?

Data about data: descriptions of elements, structures, domains, relationships, constraints, indexes, and access paths stored in the data dictionary/system catalog.

13. What is End-user data?

Business data (raw facts) of interest to users—transactions, names, measurements—distinct from metadata.

14. If the entity has a relationship with itself it is known as what kind of relationship?

Recursive relationship (a unary relationship).

15. What is a desktop database?

A single‑user database on a personal computer that supports one user at a time (e.g., small MS Access files).

16. Know the different kinds of models (entity relationship, relational data, network, hierarchical, and object-oriented).

Hierarchical: upside‑down tree (1:M). Network: graph with multiple parents. Relational: tables/relations, keys, SQL. ER: conceptual graphical entities/attributes/relationships. Object‑oriented: objects with attributes and methods, classes/inheritance (UML).

17. Know what kind of data an XML database supports (Specifically XML data).

Semistructured hierarchical textual data encoded as XML documents (tagged elements/attributes).

18. What is a surrogate key and what type of data is commonly used with it?

System‑generated primary key (commonly numeric, auto‑increment) used when no suitable natural key exists or to simplify joins/indexing.

19. What is the extended entity relationship model?

EER: ER extended with supertypes/subtypes, specialization/generalization, inheritance, subtype discriminators, disjoint/overlap and completeness constraints, and entity clusters.

20. What is a system administrator and what is their responsibilities?

Platform/OS administrator who manages servers, networks, storage, OS patches, backups and ensures infrastructure supporting the DBMS is available and performant; coordinates with DBAs.

21. What is a data administrator and what is their responsibilities?

DA/IRM: strategic role setting data policies/standards, metadata governance, and long‑term planning; controls corporate data resources (computerized and manual) and reports