CSE 511 Midterm Practice Questions With
Verified And Updated Answers
What is the difference between a data model and schema? - answer✔A data model is a
conceptual representation of how data is organized and structured within a system. It defines
the entities (or objects), their attributes, and the relationships between them.
A schema, on the other hand, refers to a specific implementation or blueprint of a database
system based on a given data model. It defines the structure, organization, and constraints of
the database, specifying the tables, columns, data types, relationships, and integrity rules. In
simple terms, a schema represents the physical or logical layout of a database.
Describe the physical schema - answer✔Physical Schema describes the files and indexes used.
Which command in a SQL query eliminates duplicate rows from query results? -
answer✔DISTINCT
What are advantages of using Heap Files for storage? - answer✔1. For fetching large proportion
of stored records for a query
2. For bulk loading of data
3. For handling relatively small relations
With respect to B+ trees, what is the purpose of non-leaf nodes? - answer✔For index entries
When creating a Relational DB from an ER diagram, which conversions take place? -
answer✔Entities become tables while converting an ER diagram to a Relational DB, and each
record is comprised of the set of attributes (columns in the table) that describe the entity.
Which of the following is created by the FROM clause, when multiple tables are listed after the
FROM clause - answer✔Cartesian Product
In the context of Index Classification, we have discussed Clustered Index versus Unclustered
Index. What is the difference between these classifications? - answer✔If the order of data
records is the same as, or close to the order of data entries, then it is called clustered.
Otherwise, it is called unclustered.
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