Database Systems Overview

To provide users with an abstract view of data and to allow access and modification of interrelated data.

Data models are conceptual tools for describing data, their relationships, semantics, and constraints.

The relational model stores all data in tables, with rows and columns representing records and attributes, respectively.

<p>Relational model and Entity-Relationship data model.</p> Signup and view all the answers

<p>Data abstraction hides the complexity of data structures from users, simplifying their interaction with the data.</p> Signup and view all the answers

<p>The physical level describes how records, such as instructors, are physically stored in the database.</p> Signup and view all the answers

<p>Consistency constraints ensure that data remains valid and accurate according to defined rules.</p> Signup and view all the answers

<p>An object-based data model allows for the representation of complex data types and relationships.</p> Signup and view all the answers

<p>The storage manager is responsible for interacting with the OS file manager, and efficiently storing, retrieving, and updating data.</p> Signup and view all the answers

<p>The key components of the storage manager include the authorization and integrity manager, transaction manager, file manager, and buffer manager.</p> Signup and view all the answers

<p>The data dictionary stores metadata about the structure of the database, particularly the schema.</p> Signup and view all the answers

<p>The query processor interprets DDL statements and compiles DML statements into evaluation plans.</p> Signup and view all the answers

<p>Query optimization is the process of selecting the lowest cost evaluation plan from various alternatives for executing a query.</p> Signup and view all the answers

<p>The storage manager implements data files, a data dictionary, and indices for fast data access.</p> Signup and view all the answers

<p>Indices provide pointers to data items that hold specific values, allowing for faster data access.</p> Signup and view all the answers

<p>The DDL interpreter's function is to interpret DDL statements and record their definitions in the data dictionary.</p> Signup and view all the answers

<p>SQL lacks capabilities for user input, output to displays, and network communication, making it less powerful than a Turing machine.</p> Signup and view all the answers

<p>Application programs generally access databases through language extensions or application programming interfaces like ODBC/JDBC.</p> Signup and view all the answers

<p>Logical design involves deciding on the database schema and determining what attributes should be recorded in the database.</p> Signup and view all the answers

<p>Physical design determines the actual layout of the database on storage systems.</p> Signup and view all the answers

<p>SQL is often embedded in higher-level languages to perform user interactions and additional computational tasks.</p> Signup and view all the answers

<p>Non-procedural languages specify what data to retrieve without detailing how to obtain it, whereas procedural languages require step-by-step instructions.</p> Signup and view all the answers

<p>A database system is typically partitioned into modules that handle various responsibilities, such as data management and performance optimization.</p> Signup and view all the answers

<p>Factors include the nature of the data, required attributes, and how those attributes can be effectively distributed across the schemas.</p> Signup and view all the answers

<p>The three types of parallel databases are shared memory, shared disk, and shared nothing.</p> Signup and view all the answers

<p>In two-tier architecture, the application resides at the client machine, while in three-tier architecture, the client communicates with an application server that accesses the database.</p> Signup and view all the answers

<p>Distributed databases are characterized by geographical distribution and schema/data heterogeneity.</p> Signup and view all the answers

<p>A database administrator (DBA) has central control over the database system and is responsible for its management.</p> Signup and view all the answers

<p>Partitioning enhances system design by separating the client from direct database calls, improving scalability and maintainability.</p> Signup and view all the answers

<p>Data redundancy and inconsistency, and difficulty in accessing data.</p> Signup and view all the answers

<p>Atomicity ensures that a transaction completes fully or does not happen at all, maintaining the database's consistency.</p> Signup and view all the answers

<p>Database systems manage concurrent access through control mechanisms to maintain data consistency.</p> Signup and view all the answers

<p>Information about students, instructors, and classes.</p> Signup and view all the answers

<p>Integrity constraints are often buried in program code rather than explicitly stated.</p> Signup and view all the answers

<p>Database systems enable concurrent access that enhances performance and efficiency.</p> Signup and view all the answers

<p>Databases centralize data storage, preventing isolation by using a unified structure for access.</p> Signup and view all the answers

<p>File systems struggle to secure access, making it hard to control user access to certain data.</p> Signup and view all the answers

<p>Application programs facilitate operations like adding students, registering for courses, and generating transcripts.</p> Signup and view all the answers

<p>Data redundancy complicates data management, leading to potential inconsistencies and increased storage costs.</p> Signup and view all the answers