23 solved GATE DA questions on Database Management & Warehousing, drawn from 3 exam years and grouped by year. Every question shows the official answer and a step-by-step solution.
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Record the schema, functional dependencies, or ER structure before choosing a rule or writing a query. SQL semantics depend on duplicate handling, NULL behavior, and grouping rules. Data warehousing questions require distinguishing facts from dimensions. These selected foundations connect the relational model, normalization, SQL, and warehousing concepts. They are not a complete syllabus.
Our study notes and original examples support the PYQs below; they are not official exam questions or a replacement for the current syllabus.
An entity set maps to a table; each relationship becomes either a table or foreign keys depending on cardinality. A weak entity's key includes its owner's key. Map total participation as a NOT NULL foreign key. Read the cardinality ratio and participation constraints before converting an ER diagram to tables.
Check yourself: Does your relational schema preserve every entity, relationship, and key constraint from the ER diagram?
Compute the attribute closure X⁺ by starting with X and repeatedly applying dependencies. X is a superkey when X⁺ contains all attributes; a candidate key has no proper subset that is also a superkey. BCNF requires every nontrivial determinant to be a superkey. A partial dependency of a non-prime attribute on a proper subset of a candidate key violates 2NF.
Check yourself: Can removing one attribute from your proposed key still determine every attribute?
SQL bags retain duplicates; relational algebra uses sets. A JOIN can multiply rows when multiple matches exist. GROUP BY partitions rows; HAVING filters groups after aggregation. COUNT(column) ignores NULLs; COUNT(*) counts all rows. A LEFT JOIN retains every row from the left table, padding with NULLs where no match exists.
Check yourself: Can you enumerate the rows produced by the JOIN before applying GROUP BY?
A schedule is conflict-serializable when its precedence graph (one vertex per transaction, edges for conflicting operation orderings) is acyclic. Two operations conflict when they access the same item and at least one writes. A topological sort of the acyclic graph gives an equivalent serial order. Recoverability is a separate property.
Check yourself: Have you excluded read-read pairs and checked every shared data item?
A star schema centers a fact table holding measures and foreign keys to dimension tables. Dimensions describe the who, what, where, and when; facts record quantitative measures. Roll-up aggregates along a dimension hierarchy (e.g., day to month); drill-down disaggregates. Slice fixes one dimension; dice restricts multiple dimensions.
Check yourself: Is each column in the fact table a measure or a foreign key, not a descriptive attribute?
Original teaching example · not a PYQ
Original mini-example: R(A, B, C, D) has functional dependencies A → B and BC → D. Find all candidate keys and the highest normal form among 1NF, 2NF, 3NF, and BCNF.
Candidate key: {A, C}. Highest normal form: 1NF (violated by the partial dependency A → B).
Separate original check: in a star schema, a fact table Sales has foreign keys to dimension tables Date, Product, and Store. Date has 365 rows, Product has 100 rows, and Store has 50 rows. What is the maximum number of distinct fact rows if no combination of dimension keys is repeated?
1,825,000 rows.
Each fact row corresponds to a unique (Date, Product, Store) combination. The maximum is 365 × 100 × 50 = 1,825,000. Actual data may be sparse, but this is the upper bound when every combination is permitted exactly once.
Supplemental reading, not an official GATE reading list or an endorsement of these notes.
Free supplemental slides from the textbook authors covering the relational model, SQL, normalization, ER diagrams, transactions, and data warehousing. Revisit the relevant chapter after attempting practice questions.
This page shows 23 recent questions from the released archive, newest first. For older questions and complete papers, browse all GATE DA papers. Questions can carry more than one subject tag; counts are not marks weightage.
Employee(EmpID, TeamID), where the column EmpID (ID of an employee) is the primary key. The column TeamID denotes the team ID of the…MSQ · +2 marks · MediumCar (model, year, serial, color) Make (maker, model) Own (owner, serial) A tuple in Car represents a specific…MCQ · +1 marks · EasyFacts(D1, D2, val), where D1 and D2 are its dimension attributes and val is a dependent attribute.…MCQ · +2 marks · MediumCustomer and Person, in a database: [code] Which of the following statements is/are correct?MSQ · +2 marks · EasyContinue learning with Success Tracker
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