Chapter 5 - Database Processing Flashcards
Columns
Also called fields.
Database
A self-describing collection of integrated records. A collection of tables plus relationships among the rows in those tables, plus special data, called metadata, that describes the structure of the database.
Rows
Also called records.
Table
Also called a file.
Primary Key
A column or group of columns that identifies a unique row in a table.
Foreign Keys
Keys of a different (foreign) table than the one in which they reside.
Relational Database
Database that carries it’s data in the form of tables and represents relationships using foreign keys.
Metadata
Data that describe data.
Database Management System (DBMS)
A program used to create, process, and administer a database. The DBMS creates tables, relationships, and other structures in the database.
Four Processing Operations of a DBMS
- Read
- Insert
- Modify
- Delete
Structured Query Language (SQL)
An international standard language for processing a database.
Database Application
A collection of forms, reports, queries, and application programs that process a database.
Form
Data entry forms are used to read, insert, modify and delete data.
Report
Reports query data using the DBMS and display the results in a structured context.
Lost-update Problem
A problem associated with multi-user processing. To prevent this problem, some type of locking must be used to coordinate the activities of users who know nothing about one another.
Data Model
A logical representation of database data created before building a database. It is essentially the blueprint of the database. Popular data models include Entity-relationship (E-R) and Unified Modeling Language (UML).
Entity
Some thing that the users want to track.
Attributes
Entities have attributes that describe characteristics of the entity. When creating a database an entity attribute becomes a table column.
Identifier
Entities have an identifier, which is an attribute (or group of attributes) whose value is associated with one and only one entity instance. When creating a database an entity identifier becomes becomes a table key.
1:N
One-to-many relationship
N:M
Many-to-many relationship. It is not written N:N, because that would imply the same number of entities on each side of the relationship.
1:1
One-to-one relationship.
Maximum Cardinality
The maximum number of entities that can be involved in a relationship. Examples are 1:N, N:M, and 1:1.
Minimum Cardinality
Constraints on minimum requirements of relationships. “What is the minimum number of entities required in the relationship?”
Normalization
The process of converting a poorly structured table into two or more well-structured tables. Normalization is done to prevent data integrity problems.
Nonrelational database
Recently developed for BigData companies. Amazon’s Dynamo, Google’s Bigtable and Facebook’s Cassandra. Also called NoSQL databases.
BigData
Data collections that are characterized by huge volume, rapid velocity and great variety.
Elastic
The number of servers can dynamically increase and decrease without disrupting performance.
Durability
One data is committed to the data store, it won’t be lost, even in the presence of failure.