Database Vocab Flashcards
Define: Database
An organized or structured collection of data, typically stored in electronic format
Define: CRUD
An acronym that stands for Create, Read, Update, and Delete. These are features of any database.
Define: Relational Database Management System
Software that manages data in an organized or structured way.
Define: Table
A two-dimensional collection of data.
Define: Relational Database
A database in which all data is stored in related tables with rows and columns
Define: Relationship
A natural association between or two or more entities.
Define: Column
A set of data values(or attributes)all of a single type.
Define: Row
Holds the fields or attributes for a specific entity. Also called a record or a tuple.
Define: Attribute
a property or description of an entity.
Define: Domain
a set of possible values for an attribute.
Define: Field
the smallest units of information you can access in a database
Define: Record
a group(row) of fields within a table that are relevant to a specific entity
Define: Entity
An object in the real world that is distinguishable from other objects and has unique characteristics or attributes.
Define: Entity Set
A collection of entities having the same characteristics or attributes
Define: Instance
A single entity of an entity set
Define: ERD
Acronym for Entity Relationship Diagram. An ERD is a diagram (or model) of a database that shows all tables and relationships between tables
Define: Relationship
A natural association between entities (objects)
Define: One-to-one Relationship
An instance of entity A is related to only one instance of entity B
Define: One-to-many Relationship
An instance of entity A is related to more than one instance of entity B
Define: Many-to-many relationship
More than one instance of entity A is related to more than one instance of entity B
Define: Primary Key
An attribute (column)or combination of attributes which can be used to uniquely identify one row from any other row in the table.
Define: Simple key
A primary key, like Part Number, which contains only one attribute (column)
Define: Composite key
A primary key which is made from the combination of more than one attribute (column)
Define: Foreign key
A column or combination of columns that is used to establish and enforce a link between the data in two tables.
Define: Natural key
A key that is formed of attributes that already exist in the real world
Define: Synthetic(Surrogate)Key
Keys that don’t have a natural relationship with, and are not derived from, the rest of the columns in a table
Define: Normalization
The process of organizing data in order to reduce redundancy by dividing a database into two or more tables and then defining table relationships.
Define: Null
The word used to indicate that a field in a record is empty
Define: Junction (bridge)table
A table used to implement many-to-many relationships
Define: SQL
Structured Query Language. A language written specifically to implement relational databases.
Define: Query
An inquiry that returns information back from the database that meets certain criteria.
Define: Data Definition Language (DDL)
A subset of SQL that contains SQL statements to create or delete databases and tables.
Define: Data Manipulation Language (DML)
A subset of SQL that contains SQL statements to add, update or delete data from tables.
Define: Data Query Language (DQL)
A subset of SQL that contains SQL statements to structure queries to retrieve specific data from a database.
Define: Data Control Language (DCL)
A subset of SQL that contains SQL statements that provide administrative control of databases.
Define: Entity integrity
Entity integrity means that every table must have a primary key
Define: Referential integrity
A foreign key must have a matching primary key or it must be null
Define: Atomic value
A value that is indivisible as far as the relational model is concerned
Define: Schema
The structure or design of a database
Define: Index
A data structure that improves the speed of data retrieval operations on a database table
Define: Cardinality
The number of occurrences in one entity which are associated (or linked) to the number of occurrences in another entity
Define: Tuple
A row or a record of a table.
