1. Information is stored in databases.
-Database – maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses)
2. Database models include:
-Hierarchical database model – information is organized into a tree-like structure (using parent/child relationships) in such a way that it cannot have too many relationships
-Network database model – a flexible way of representing objects and their relationships Relational database model – stores information in the form of logically related two-dimensional tables
-Entity – a person, place, thing, transaction, or event about which information is stored
The rows in each table contain the entities
In Figure 7.1 CUSTOMER includes Dave’s Sub Shop and Pizza Palace entities
-Attributes (fields, columns) – characteristics or properties of an entity class
The columns in each table contain the attributes
In Figure 7.1 attributes for CUSTOMER include Customer ID, Customer Name, Contact Name
Primary keys and foreign keys identify the various entity classes (tables) in the database.
-Primary key – a field (or group of fields) that uniquely identifies a given entity in a table
-Foreign key – a primary key of one table that appears an attribute in another table and acts to provide a logical relationship among the two tables
3. Database advantages from a business perspective include
-Increased flexibility
-Increased scalability and performance
-Reduced information redundancy
-Increased information integrity (quality)
-Increased information security
4. Increased flexibility
-A well-designed database should:
-Handle changes quickly and easily
-Provide users with different views
-Have only one physical view
-Physical view – deals with the physical storage of information on a storage device
-Have multiple logical views
-Logical view – focuses on how users logically access information
5. Increased scalability and performance
-A database must scale to meet increased demand, while maintaining acceptable performance levels
-Scalability – refers to how well a system can adapt to increased demands
-Performance – measures how quickly a system performs a certain process or transaction
-Reduced information redundancy
-Databases reduce information redundancy
-Redundancy – the duplication of information or storing the same information in multiple places
Inconsistency is one of the primary problems with redundant information
6. Increase Information Integrity (Quality)
-Information integrity – measures the quality of information
-Integrity constraint – rules that help ensure the quality of information
-Relational integrity constraint
-Business-critical integrity constraint
7. Increased information security
2. Database models include:
-Hierarchical database model – information is organized into a tree-like structure (using parent/child relationships) in such a way that it cannot have too many relationships
-Network database model – a flexible way of representing objects and their relationships Relational database model – stores information in the form of logically related two-dimensional tables
-Entity – a person, place, thing, transaction, or event about which information is stored
The rows in each table contain the entities
In Figure 7.1 CUSTOMER includes Dave’s Sub Shop and Pizza Palace entities
-Attributes (fields, columns) – characteristics or properties of an entity class
The columns in each table contain the attributes
In Figure 7.1 attributes for CUSTOMER include Customer ID, Customer Name, Contact Name
Primary keys and foreign keys identify the various entity classes (tables) in the database.
-Primary key – a field (or group of fields) that uniquely identifies a given entity in a table
-Foreign key – a primary key of one table that appears an attribute in another table and acts to provide a logical relationship among the two tables
3. Database advantages from a business perspective include
-Increased flexibility
-Increased scalability and performance
-Reduced information redundancy
-Increased information integrity (quality)
-Increased information security
4. Increased flexibility
-A well-designed database should:
-Handle changes quickly and easily
-Provide users with different views
-Have only one physical view
-Physical view – deals with the physical storage of information on a storage device
-Have multiple logical views
-Logical view – focuses on how users logically access information
5. Increased scalability and performance
-A database must scale to meet increased demand, while maintaining acceptable performance levels
-Scalability – refers to how well a system can adapt to increased demands
-Performance – measures how quickly a system performs a certain process or transaction
-Reduced information redundancy
-Databases reduce information redundancy
-Redundancy – the duplication of information or storing the same information in multiple places
Inconsistency is one of the primary problems with redundant information
6. Increase Information Integrity (Quality)
-Information integrity – measures the quality of information
-Integrity constraint – rules that help ensure the quality of information
-Relational integrity constraint
-Business-critical integrity constraint
7. Increased information security
-Information is an organizational asset and must be protected
-Databases offer several security features including:
-Password – provides authentication of the user
-Access level – determines who has access to the different types of information
-Access control – determines types of user access, such as read-only access
8. Database Management Systems
-Direct interaction –
The user interacts directly with the DBMS
The DBMS obtains the information from the database
-Databases offer several security features including:
-Password – provides authentication of the user
-Access level – determines who has access to the different types of information
-Access control – determines types of user access, such as read-only access
8. Database Management Systems
-Direct interaction –
The user interacts directly with the DBMS
The DBMS obtains the information from the database
-Indirect interaction
User interacts with an application (i.e., payroll application, manufacturing application, sales application)
The application interacts with the DBMS
The DBMS obtains the information from the database
User interacts with an application (i.e., payroll application, manufacturing application, sales application)
The application interacts with the DBMS
The DBMS obtains the information from the database
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