Database Management Ch. 1 Glossary Terms

ACID Properties

An acronym (Atomicity, Consistency, Isolation, Durability) representing a set of properties that guarantee that database transactions are processed reliably.

Application Program Interface (API)

A set of routines, protocols, and tools for building software applications, often used by applications to send SQL queries to a database (e.g., ODBC, JDBC).

Application Programs

Software tools that use embedded SQL within a host language to interact with a database, handling user input, processing data, and displaying results.

Atomicity

An ACID property ensuring that a transaction is treated as a single, indivisible unit of operations; either all operations are completed successfully, or none are.

Authorization and Integrity Manager

A component of the storage manager that ensures only authorized users can access/modify data and that all modifications comply with integrity constraints.

Buffer Manager

A component of the storage manager that manages the buffer pool (a reserved area of main memory) to store frequently accessed data, reducing disk access and improving performance.

Centralized Database

A database architecture where all data is stored and managed in a single system, simplifying management but potentially becoming a bottleneck.

Client-Server Architecture

A database architecture where a central server handles requests from multiple client machines, allowing for scalable solutions.

Concurrency Control Manager

A component of the transaction management system that ensures multiple transactions can occur simultaneously without causing inconsistencies.

Consistency

An ACID property ensuring that a transaction brings the database from one valid state to another, maintaining all defined rules and constraints.

Data Definition Language (DDL)

A specification notation used to define the database schema, including creating, altering, and deleting database structures like tables and indexes.

DDL Compiler (DDL Interpreter)

A component of the query processor that processes DDL statements and records the definitions in the data dictionary.

Data Dictionary (System Catalog)

Stores metadata (data about data) about the database, including the schema, integrity constraints, and authorization information.

Data Files

Actual files where the database data (table rows, columns, etc.) is stored.

Data Independence

The ability to modify the schema at one level of a database system without requiring changes at higher levels (e.g., physical data independence, logical data independence).

Data Isolation

A problem in file-based systems where data is scattered across multiple files in different formats, making integration difficult.

Data Manipulation Language (DML)

A language used to access and update data organized according to the chosen data model, performing operations like retrieval, insertion, deletion, and modification.

DML Compiler

A component of the query processor that translates DML statements into an evaluation plan of low-level instructions and performs query optimization.

Data Model

A collection of tools for describing data, data relationships, data semantics, and data constraints (e.g., relational, ER, object-based).

Data Redundancy and Inconsistency

A problem in file-based systems where the same data is stored in multiple places, leading to duplication and potential conflicts if not all copies are updated.

Database Administrator (DBA)

A person with central control over the database system, responsible for schema definition, security, maintenance, and optimization.

Database Architecture

The design and structure of a database system, determining how data is stored, managed, and accessed (e.g., centralized, client-server, parallel, distributed).

Declarative DML (Non-Procedural DML)

A type of DML where users specify what data is needed without detailing how to retrieve it (e.g., SQL).

Distributed Database

A database architecture where data is stored across multiple geographical locations, each with its own database system, providing high availability and fault tolerance.

Durability

An ACID property ensuring that once a transaction has been committed, it will remain permanent, even in the event of system failures.

Embedded SQL

SQL code embedded within a host programming language (e.g., C++, Java, Python) to allow for complex queries and control structures.

Entity-Relationship (ER) Model

A data model primarily used for database design, using entities and relationships to visualize the structure of a database.

File Manager

A component of the storage manager responsible for allocating space on disk storage for database files and handling their creation, deletion, and organization.

Host Language

A higher-level programming language (e.g., C, Java, Python) in which SQL queries are embedded to overcome SQL's limitations in complex computations and I/O.

Indices

Data structures that provide fast access to data items in the database by creating pointers to specific values, similar to an index in a book.

Instance

The actual content of the database at a particular point in time; a snapshot of the data.

Integrity Constraints

Rules that the data in a database must follow (e.g., a unique ID, an account balance greater than zero).

Isolation

An ACID property ensuring that concurrent transactions appear to execute in isolation from each other, preventing interference.

Logical Design

The phase of database design focused on defining the database schema, identifying attributes, and organizing them into relations.

Logical Level (Conceptual Schema)

The middle level of database abstraction, describing what data is stored and the relationships among it, independent of physical storage.

Logical Schema

The overall logical structure of the database, defining the types of data, relationships, and rules.

Metadata

Data about data; information that describes the structure, organization, and constraints of the database, stored in the data dictionary.

Optimization

The stage in query processing where the optimizer generates and evaluates various execution plans to select the most efficient one (lowest cost).

Parallel Database

A database designed to take advantage of multiple processors and cores for parallel data processing, with architectures like shared memory, shared disk, or shared nothing.

SQL (Structured Query Language)

A widely used, non-procedural query language for managing and manipulating relational databases.

Procedural DML

A type of DML where users must specify what data is needed and how to get it, involving explicit steps for retrieval.

Query Processor

A database system component that interprets and executes database queries, converting high-level queries into low-level instructions.

Schema

The overall logical structure of the database (logical schema) or the physical layout of the data (physical schema).

Relational Model

The most widely used data model, organizing data into tables (relations) consisting of rows (records/tuples) and columns (attributes).

Three-Tier Architecture

A database application architecture with a client layer, an application server layer (containing business logic), and a database layer, enhancing scalability, security, and maintainability.

Two-Tier Architecture

A database application architecture where the application logic resides on the client machine, which directly interacts with the database server.

Turing Complete

A property of a programming language or system indicating it can perform any computation that a universal Turing machine can; SQL is not Turing complete.

Transaction

A collection of operations that together perform a single logical function, adhering to ACID properties.