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10 Cards in this Set
- Front
- Back
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1) What is the purpose of an E-R Model?
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The purpose of the E-R Model is to "serve as the logical representation of the physical system to be built" (Casteel, 2007, p. 5). Moreover, the E-R Model eliminates anomalies and data inconsistencies.
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2) Discuss the problems that can be caused by data redundancy.
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Some of the problems that data redundancy can cause are the following:
(a) Information is repeated, which is unnecessary. (b) Data anomalies can result from redundancy. |
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3) Explain the role of a primary keys and of foreign keys.
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Role of primary keys is to "uniquely [identify] each record" (Casteel, 2007, p. 8). Role of foreign keys is "to establish a relationship with another table or tables" (p. 11). In other words, the foreign key serves as an attribute whose values match primary key values in the related tables.
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4) List and explain the steps of the normalization process.
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(a) 1NF: Eliminate all repeating values, and identify a primary key or primary composite key.
(b) 2NF: Make certain the table is in 1NF, and eliminate any partial dependencies. (c) 3NF: Make certain the table is in 2NF, and remove any transitive dependencies. |
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5) Identify at least three reasons an organization might analyze historical sales data stored in its database.
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(a) To predict which products are more popular, analyzing historical sales data will help an organization decide which product(s) and how many of it they should order from the distributor.
(b) Analyzing historical data can also help determine the overall sales performance of the organization. (c) It is also possible to predict which new products would be in demand by analyzing the trend of the sales. |
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Database
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logical structure to store data
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Database Management System (DBMS)
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software used to create and interact with the database
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Database Components
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- Character
- Field - Record - File |
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Database Components - Character?
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- Basic unit of data
- Can be a letter, number, or special symbol |
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Database Components - Field?
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- A group of related characters
- Represents an attribute or characteristic of an entity - Corresponds to a column in the physical database |
