Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
45 Cards in this Set
- Front
- Back
Database |
A set of interrelated, centrally coordinated data files that are stored with as little data redundancy as possible |
|
Database management system (DBMS) |
Manages and controls the data. Interfaces between the data and the application programs that use the data stored in the database |
|
Database system |
The database, the DBMS, and the application programs that access the database through the DBMS |
|
Database administrator (DBA) |
Responsible for coordinating, controlling, and managing the database |
|
Data warehouse |
One or more very lage databases containing both detailed and summarized data for a number of years that is used for *analysis* (not transaction processing) |
|
Business intelligence |
Analyzing large amounts of data for strategic decision |
|
Online analytical processing (OLAP) |
Using queries to investigate hypothesized relationships among data |
|
Data mining |
Sophisticated statistical analysis, including AI techniques such as neural networks, to discover unhypothesized relationships in the data |
|
Scrubbing the data |
Verifying the accuracy of data |
|
Data integration |
One advantage of a DBS. Master files are combined into large "pools" of data that many application programs access |
|
Data sharing |
Another advantage of a DBS. All data under one system can be shared among authorized users |
|
Minimal data redundancy and data inconsistencies |
Another advantage of a DBS. Data items are stored only once |
|
Data independence |
Another advantage of a DBS. The [data] and the [programs that use them] are independent of each other, so that each can be changed without changing the other. Facilitates programming and simplifies data management |
|
Cross-functional analysis |
Another advantage of a DBS. Relationships can be explicitly defined and used in the preparation of management reports (ie, the association between selling costs and promotional campaigns) |
|
Record layout |
A document that shows the items stored in a file, including the order and length of the data fields, and the type of data stored in the file |
|
Database approach |
Provides two separate views of the data: the physical view and the logical view |
|
Logical view |
Conceptual. How people conceptually organize and understand the relationships among data items |
|
Physical view |
Physical. The way data are physically arranged and stored in the computer system |
|
Schema |
A description of the [data elements] in a database, the [relationships] among them, and the [logical model] used to organize and describe the data |
|
Conceptual level schema |
Overall concept. Entire database. The organization-wide view of the entire database. Lists all data elements and the relationships among them |
|
External-level schema |
An individual user's view of portions of a database |
|
Subschema |
An external-level schema is called a subschema |
|
Internal-level schema |
A low-level view of the DB. Describes how the data are stored and accessed, including record layouts, definitions, addresses, and indexes |
|
Data dictionary |
Defines each data element in the database. Contains information about the structure of the DB. For each data element stored in the DB, there is a record in the dictionary describing it. |
|
Data definition language |
Builds the data dictionary, creates the database, describes logical views for each user, and specifies record or field security constraints |
|
Data manipulation language (DML) |
Changes database content, including data element creations, updates, insertions, and deletions |
|
Data query language (DQL) |
High-level, English-like language that contains powerful, easy-to-use commands that enable users to retrieve, sort, order, and display data |
|
Report writer |
Simplifies report creation. Users specify the data elements they want printed, and the report writer searches the DB, extracts the data elements, and prints them in the user-specified format |
|
Data model (logical data model) |
Abstract representation of database contents |
|
Relational data model |
Represents conceptual- and external-level schemas as if data are stored in two-dimensional tables |
|
Tuple (rhymes with couple) |
A row in a table |
|
Primary key |
The database attribute, or combination of attributes, that uniquely identifies a specific row in a table (a tuple) |
|
Foreign key |
An attribute in a table that is also a primary key in another table and is used to link the two tables |
|
Update anomaly |
Occurs when data values are not updated correctly. When the address is updated in one location and not the others, an update anomaly occurs, and data inconsistencies result |
|
Insert anomaly |
Inability to add records to a database because attributes of one entity are stored in the record of a different entity. Solution: create two separate tables for each of the two entities, then link the two tables |
|
Delete anomaly |
Occurs when deleting a row has unintended consequences. Deleting a row loses all information about that entity. Again: have a sales table, and a customer table, then link the two |
|
Relational database |
A database using the relational data model |
|
Every column in a row must be single valued |
In a relational DB, there can only be one value per cell |
|
Primary keys cannot be null |
A primary key cannot uniquely identify a row in a table if it is null (blank) |
|
Entity integrity rule |
A nonnull primary key ensures that every row in a table represents something and that it can be identified |
|
Foreign keys, if not null, must have values that correspond to the value of a primary key in another table |
Foreign keys link rows in one table to rows in another table |
|
Referential integrity rule |
Foreign keys which link rows in one table to rows in another table must have values that correspond to the value of a primary key in another table. This is to ensure database consistency |
|
Normalization |
Following relational database creation rules to design a relational database that is free from delete, insert, and update anomalies. It's one way to design a DB by assuming that everything is initially stored in one large table |
|
Third normal form (3NF) |
Decompose the initial large table into a set (many, multiple) of tables. Free of update, insert, and delete anomalies |
|
Semantic data modeling |
The designer uses knowledge of business processes and information needs to create a diagram that shows what to include in the database. This diagram is then used to create a set of relational tables that are already in 3NF |