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Android Database Apps: Volume 1: Planning
1.1. Overview
The software engineering discussed in this volume applies to many platforms, environments, and languages; not just Android database apps. We have selected a set of software engineering strategies and techniques that will ensure we have organized our data properly and our code logic is correct. We should plan for minimal deprecation because this can be costly for developers and users.
1.2. The role of a software engineer
A software engineer is similar to a construction engineer in that they are both concerned with drawing up plans to determine how their organizations will build their products. Software engineers produce specifications for software products, and programmers implement these specifications to realize those products.
1.3. Object theory
Object theory is concerned with the classification of objects and their behaviors, and the relationships between objects. In relational database design, we refer to real-world objects as 'entities'. Later, when we start to implement engineering specifications as executable software, we'll use the term 'objects'. We use the inherent properties of objects, and their relationships with other objects, to build a conceptual structural model that does not include the behaviors of objects.
1.4. Requirements analysis
We use an adaptation of the Waterfall Model for our software creation and development. Other industries, such as the construction and motor car industries, also use this model. It is easier to grow a model of a system than it is to shrink one. Therefore, as we model our system, we keep the number of entities, attributes, and entity relationships to a minimum.
1.5. Relational databases
Designing relational databases is challenging. Although our discussion of relational databases is concise, we need to think carefully about the concepts, practice the techniques thoughtfully, and form a clear picture of the real-world systems we want to model. Memorizing a set of facts in a subject like this is not enough to become a skilled database designer.
A relational database has two essential
- Online Transaction Processing (OLTP), where an organization uses its database for everyday business transactions. For example, an organization may store details of its customers and suppliers to make its business more efficient.
- Online Analytical Processing (OLAP), where an organization uses the data in its database to analyze its business. For example, an organization may find it useful to know how many customers have purchased a certain item since they upgraded the item and increased its price. This kind of information can be important for making decisions.
In this book, we discuss two approaches to database
- Object-oriented database design. This involves modeling real-world systems and enables us to become familiar with the entities of those systems by understanding their attributes and relationships.
- Logical database design. These techniques use mathematical principles established in the 1970s by Edgar J Codd - an English computer scientist. This approach uses mathematical reasoning to protect the database from anomalies. Many database designers use a combination of these approaches.
1.6. Method specification
We strive to produce software that is completely free from logical errors. We identify the objectives of code blocks and express them with boolean logic. We test our logic with all possible inputs before releasing our software updates. We identify the objectives of a method from its description and use them to write informal and formal post-conditions. A method's post-condition is boolean, and we verify it with unit testing.
The software engineering discussed in this volume applies to many platforms, environments, and languages; not just Android database apps. We have selected a set of software engineering strategies and techniques that will ensure we have organized our data properly and our code logic is correct. We should plan for minimal deprecation because this can be costly for developers and users.
1.2. The role of a software engineer
A software engineer is similar to a construction engineer in that they are both concerned with drawing up plans to determine how their organizations will build their products. Software engineers produce specifications for software products, and programmers implement these specifications to realize those products.
1.3. Object theory
Object theory is concerned with the classification of objects and their behaviors, and the relationships between objects. In relational database design, we refer to real-world objects as 'entities'. Later, when we start to implement engineering specifications as executable software, we'll use the term 'objects'. We use the inherent properties of objects, and their relationships with other objects, to build a conceptual structural model that does not include the behaviors of objects.
1.4. Requirements analysis
We use an adaptation of the Waterfall Model for our software creation and development. Other industries, such as the construction and motor car industries, also use this model. It is easier to grow a model of a system than it is to shrink one. Therefore, as we model our system, we keep the number of entities, attributes, and entity relationships to a minimum.
1.5. Relational databases
Designing relational databases is challenging. Although our discussion of relational databases is concise, we need to think carefully about the concepts, practice the techniques thoughtfully, and form a clear picture of the real-world systems we want to model. Memorizing a set of facts in a subject like this is not enough to become a skilled database designer.
A relational database has two essential
- Online Transaction Processing (OLTP), where an organization uses its database for everyday business transactions. For example, an organization may store details of its customers and suppliers to make its business more efficient.
- Online Analytical Processing (OLAP), where an organization uses the data in its database to analyze its business. For example, an organization may find it useful to know how many customers have purchased a certain item since they upgraded the item and increased its price. This kind of information can be important for making decisions.
In this book, we discuss two approaches to database
- Object-oriented database design. This involves modeling real-world systems and enables us to become familiar with the entities of those systems by understanding their attributes and relationships.
- Logical database design. These techniques use mathematical principles established in the 1970s by Edgar J Codd - an English computer scientist. This approach uses mathematical reasoning to protect the database from anomalies. Many database designers use a combination of these approaches.
1.6. Method specification
We strive to produce software that is completely free from logical errors. We identify the objectives of code blocks and express them with boolean logic. We test our logic with all possible inputs before releasing our software updates. We identify the objectives of a method from its description and use them to write informal and formal post-conditions. A method's post-condition is boolean, and we verify it with unit testing.
80 pages, Kindle Edition
Published December 7, 2024
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