問14
頻出度★★★
業務で利用するデータの構造を分析し, 抽出したエンティティとエンティティ間の関係を E-R 図などで整理する手法はどれか。
平成21年度 秋期 ITパスポート試験 問14
テクノロジ系データベース › データベース設計
This question's explanation and your answers so far.
解説
問 14
Incorrectア
Data cleaning is the work of detecting and correcting errors, duplicates, inconsistent notation, and missing values in accumulated data in order to improve data quality (essentially the same as data cleansing). It tidies up the contents of existing data; it does not extract entities and relationships to design a data structure.
Incorrectイ
Data cleansing is likewise the quality-improving work of finding and fixing errors and inconsistencies in data before loading it into a data warehouse or similar system. Its target is the values of the data, not its structure, and it is not a method for organizing relationships between entities with an E-R diagram.
Incorrectウ
Data mining is a method that analyzes large volumes of accumulated data with statistical techniques or machine learning to discover previously unknown patterns or correlations, such as combinations of products that tend to be bought together. What it analyzes is data that has already been accumulated; it is not a method for designing a data structure.
- エ
正解 The correct answer is エ, data modeling. Data modeling is a method that analyzes the data handled in business operations, identifies the things and matters to be managed, that is, the entities, the relationships between them, and the attributes each entity has, and then organizes and expresses them in a diagram such as an E-R diagram. The phrases in the question, analyzing the structure of the data, the relationships between the extracted entities, and organizing them with an E-R diagram, all describe exactly what data modeling does. The E-R diagram (entity-relationship diagram) is the representative notation used in data modeling, and the data model built here becomes the foundation for later designing the tables of a relational database.
ここがポイント
- Data modeling means extracting entities, their attributes, and the relationships between entities from business data, expressing them in an E-R diagram or similar form, and thereby building the foundation for database design.
- How to tell the confusing data-something terms apart: cleaning and cleansing improve quality by correcting errors in data values, mining discovers knowledge from accumulated data, and modeling designs the data structure.
用語