Database Management Extra 2 (a) Flashcards Preview

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Flashcards in Database Management Extra 2 (a) Deck (10)
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1
Q

??? : using more space than is necessary to record data.

??? : number of different attributes that are all naturally related to 1 business entity.

??? : deletion, update, and insertion anomalies; redundancy and multiple themes in lists create modification anomalies.

A

redundant info / business theme (concepts) / list issues

2
Q

are designed to address many of the info complexity issues that arise in business; uses tables with columns and rows, columns represent different attributes of an entity, and each row represents an instance of the entity. Different tables and having a relationship between those tables. Tables are joined together using matched pairs of values.

A

Relational Databases

3
Q

minimizes data redundancy, preserves complex relationships among topics and allows for partial data (null values), can generate reports etc …

A

Relational Databases 2

4
Q

serves as intermediary between database apps and the database, DBMS manages and controls database activities, DBMS creates, processes, and admins the database it controls; can enforce rules, provide security, perform data backup and recovery.

A

DBMS (software program)

5
Q

??? ??? ??? : ensure values of column in one table are valid based on values in another table.

??? ??? : set of 1 or more computer programs or websites that serve as intermediary between user and DBMS.

A

Referential Integrity Constraint / Database Apps

6
Q

something of importance to user or org. that needs to be represented in a database, represents one theme, topic or business concept; entity-relationship model : entities are restricted to things that can be represented using a single table.

A

entity

7
Q

rows contain data about instances of an entity; columns contain data about attributes of the entity; cells of table hold a single value; all values in column are same data type; each column has a unique name; order of columns/rows is not important; no 2 rows of values can be identical.

A

Characteristics of a Relation

8
Q

Mean the same thing : table, file, relation — row, record, tuple — column, field, attribute.

keys : is 1 or more columns of a relation whose values are used to identify a row.

??? ??? : values within key column will all be unique within the entire table.

??? ??? : key composed of 2 or more attributes (columns) or values in a table for a key to be unique it must often become a composite key.

A

info / Unique Key / Composite Key

9
Q

??? ???: is a candidate key chosen to be main key for the relation; if you know value of primary key then you will be able to uniquely identify a single row within a table.

??? ??? : is unique numeric value added to relation to serve as primary key, surrogate keys are usually hidden on forms, queries and report and have no meaning to users, surrogate key often used in place of composite primary key.

A

Primary Key / Surrogate Key

10
Q

??? ??? : used to est. relationships, is a primary key from one table that is placed into another table, key is called foreign key in that table that receives the key (or a new column is created in another table by the primary key and this column is called the foreign key), used to link records together.

??? ??? : states that every value of foreign key must match a value of an existing primary key.

A

Foreign Key / Referential Integrity