What is a Relation Schema and a Relation?
A relation Schema denoted by R(A1, A2, …, An) is made up of the relation name R and the list of attributes Ai that it contains. A relation is defined as a set... Read more »
‘Database Interview Questions’ - KyaPoocha.com
What is Data Storage - Definition Language?
The storage structures and access methods used by database system are specified by a set of definition in a special type of DDL called data storage-definition language. Read more »
What is Set-at-a-time or Set-oriented?
The High level or Non-procedural DML can specify and retrieve many records in a single DML statement. This retrieve of a record is said to be Set-at-a-time or Set-oriented. Read more »
What is normalization?
It is a process of analysing the given relation schemas based on their Functional Dependencies (FDs) and primary key to achieve the properties Minimizing redundancy Minimizing... Read more »
What is Functional Dependency?
A Functional dependency is denoted by X Y between two sets of attributes X and Y that are subsets of R specifies a constraint on the possible tuple that... Read more »
When is a functional dependency F said to be minimal?
Every dependency in F has a single attribute for its right hand side. We cannot replace any dependency X A in F with a dependency Y A where Y is a proper... Read more »
What are partial, alternate,, artificial, compound and natural key?
Partial Key:It is a set of attributes that can uniquely identify weak entities and that are related to same owner entity. It is sometime called as Discriminator. Alternate... Read more »
What is indexing and what are the different kinds of indexing?
Indexing is a technique for determining how quickly specific data can be found. Types: Binary search style indexing B-Tree indexing Inverted list indexing Memory... Read more »
What is system catalog or catalog relation? How is better known as?
A RDBMS maintains a description of all the data that it contains, information about every relation and index that it contains. This information is stored in a collection... Read more »
What is join dependency and inclusion dependency?
Join Dependency:A Join dependency is generalization of Multivalued dependency.A JD {R1, R2, …, Rn} is said to hold over a relation R if R1, R2, R3, …, Rn is... Read more »
What is durability in DBMS?
Once the DBMS informs the user that a transaction has successfully completed, its effects should persist even if the system crashes before all its changes are reflected... Read more »
What do you mean by atomicity and aggregation?
Atomicity:Either all actions are carried out or none are. Users should not have to worry about the effect of incomplete transactions. DBMS ensures this by undoing... Read more »
What is a checkpoint and When does it occur?
A Checkpoint is like a snapshot of the DBMS state. By taking checkpoints, the DBMS can reduce the amount of work to be done during restart in the event of subsequent... Read more »
Brief theory of Network, Hierarchical schemas and their properties
Network schema uses a graph data structure to organize records example for such a database management system is CTCG while a hierarchical schema uses a tree data... Read more »
What is a query?
A query with respect to DBMS relates to user commands that are used to interact with a data base. The query language can be classified into data definition language... Read more »
What do you mean by Correlated sub query?
Sub queries, or nested queries, are used to bring back a set of rows to be used by the parent query. Depending on how the sub query is written, it can be executed... Read more »
What is RDBMS KERNEL?
Two important pieces of RDBMS architecture are the kernel, which is the software, and the data dictionary, which consists of the system-level data structures used... Read more »
Define SQL and state the differences between SQL and other conventional programming Languages
SQL is a nonprocedural language that is designed specifically for data access operations on normalized relational database structures. The primary difference between... Read more »
What is an Oracle Instance?
The Oracle system processes, also known as Oracle background processes, provide functions for the user processes—functions that would otherwise be done by the... Read more »
What are database files, control files and log files. How many of these files should a database have at least? Why?
Database Files The database files hold the actual data and are typically the largest in size. Depending on their sizes, the tables (and other objects) for all the... Read more »