Database Analysis Database Design - amazonia.fiocruz.br

Database Analysis Database Design - all? regret

Data analysis is the process of making sense of data and delivering insights that drive business decisions. Data analytics on the other hand is a discipline that handles the complete management of data. In this article we first take a closer look at data analysis. Data analysis has been part of research and business operations for decades. It starts with a research question or a business problem that needs to be addressed. Data is then acquired, processed, and analyzed to find the answers. Database Analysis Database Design

Programming & Tech

It has since become the dominant database model for commercial applications in comparison with other database models such as hierarchical, network and object models. A relational database organizes data in tables https://amazonia.fiocruz.br/scdp/essay/calculus-on-manifolds-amazon/marxism-and-the-state-an-analytical-approach.php relations. A table is made up of rows and columns. A row is also called a record or tuple.

Big Data and Location Analytics

A column is also called a field or attribute. A database table is similar to a spreadsheet. However, the relationships that can be created among the tables enable a relational database to efficiently store huge amount of data, and effectively retrieve selected data. Database design is Database Analysis Database Design art than science, as you have to make many decisions. Databases are usually customized Databaase suit a particular application. No two customized applications are alike, and hence, no two database are alike. Guidelines usually in terms of what not to do instead of what to do are provided in making these design decision, but the choices ultimately rest on the you - the designer. Once you have decided on the purpose of the database, gather the data that are needed to be stored in the database.

Divide Desgin data into subject-based tables. Choose one column or here few columns as the so-called primary keywhich uniquely identify the each of the rows.

In the relational model, a table cannot contain duplicate rows, because that would create ambiguities in retrieval. To ensure uniqueness, each table should have a column or a set of columnscalled primary keythat uniquely identifies every records of the table.

For example, an unique number customerID can be used as the primary key for the Customers table; productCode for Products table; isbn for Books table. A primary key is called a simple key if Database Analysis Database Design is a single column; it is called a composite key if it is made up of several columns.

You have to decide which column s is to be used for primary key. The decision may not be straight forward but the primary key shall have these properties:. Let's illustrate with an example: a table customers contains columns lastNamefirstNamephoneNumberaddresscitystatezipCode. Name may not be unique.

Phone number and address may change. Hence, it is better to create Database Analysis Database Design fact-less auto-increment number, say customerIDas the primary key. A database consisting of independent Database Analysis Database Design unrelated tables serves little purpose you may consider to use a spreadsheet instead. The power of relational database lies in source relationship that can be defined between tables.

The most crucial aspect in designing a relational database is to identify the relationships among tables. The types of relationship include:. In a "class roster" database, a teacher may teach zero or more classes, while a class is taught by one and only one teacher. In a "company" database, a manager manages zero or more employees, while an employee is managed by one and only one manager. In a "product sales" database, a customer may place many orders; while an order is placed by one particular customer. This kind of relationship is known as one-to-many. One-to-many relationship cannot be represented in a single table.

For example, in a "class roster" database, we may begin with a table called Teacherswhich stores information about Analhsis such as nameofficephone and email. To store the classes taught by each teacher, we could create columns class1class2class3but faces a problem immediately on how many columns to create. On the other hand, Database Analysis Database Design we begin with a table called Classeswhich stores information about a class courseCodedayOfWeektimeStart and timeEnd ; we could create additional columns to store information about the one teacher such as nameofficephone and email.

Data Analysis

However, since a teacher may teach many classes, its data would be duplicated in many rows in table Classes. To support a one-to-many relationship, we need to design two tables: a table Classes to store information about the classes with classID as the primary key; and a table Teachers to store information about teachers with teacherID as the primary key. We can then create the one-to-many relationship by storing the primary key of the table Teacher i.]