# An Introduction of NoSQL Databases Based on Their Categories and Application Industries +
## 4 Choose an Appropriate Database
### Database Selection Case 1  
Suppose that a 3C shopping website uses an RDB to store data for a long period of time, and this RDB generates 300,000 records per day. Users reflect that the website is slower, and hope the data processing speed to be as fast as possible, so the business owner asks the information department staff to solve this problem.  
The head of the information department traced the reasons according to the boss instructions and found that the reasons for the slower access speed of the data are not only a large amount of data generated every day but also the need for many users to merge several tables of RDB with a  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Categories of NoSQL Databases** & **Suitable Data Features** \\ \hline Wide Column Store & Three-dimensional data. \\ Applications that often search for specific field data. \\ \hline Document Store & Semi-structured files, such as XML, JSON, and so on. \\ \hline Key Value Store & One-dimensional data, which is stored in key-value pairs. \\ \hline \multirow{3}{*}{Graph Databases} & Data stored in a graphic structure. \\  & Suitable for data of social network relations, recommendation systems, and so on. \\ \hline \multirow{2}{*}{Multimodel Databases} & Determine data features suitable processing based on the data format of a specific database. \\ \hline \multirow{3}{*}{Object Databases} & The object-oriented concepts are used to describe the data itself and the relationship among the data. \\  & Suitable for computer aided design (CAD) and office automation. \\ \hline Grid and Cloud Database Solutions & Applications that need to search recent access data frequently. \\ \hline XML Databases & Data stored in XML files. \\ \hline Multidimensional Databases & Applications that often analyze data in multiple dimensions. \\ \hline Multivalue Databases & Data with multivalued attributes or composite attributes. \\ \hline \multirow{2}{*}{Event Sourcing} & Data with events that occurred in the past for tracking the status \\  & of something. \\ \hline Time Series Databases & Data related to time series. \\ \hline Other NoSQL Related Databases & Unable to know. \\ \hline Scientific and Specialized DBs & Data suitable for scientific research or computing. \\ \hline Unresolved and Uncategorized & Data based on the data format of a specific database. \\ \hline \hline \end{tabular}
\end{table}
Table 7: Summary of suitable data features for NoSQL databases.  
large amount of data. Therefore, the supervisor recommends using the NoSQL database as a solution because NoSQL databases can merge some tables of RDB in advance so that when querying a NoSQL database, the desired data can be read quickly without waiting much time to do join operations.  
After the business owner agrees, the head of the information department will then decide which NoSQL database to use. The decision process is as follows.  
1. The most suitable category of NoSQL database is the wide column store because access to the database often requires searching for data in a specific field.
2. According to the DB-Engines Ranking website [15], the wide column store databases that are more commonly discussed on the internet are Apache Cassandra and Apache HBase.
3. According to the experimental results of [PERSON] et al. [26], the time of Apache HBase to read data is less than that of Apache Cassandra. Therefore, Apache HBase is recommended as the NoSQL database used by the enterprise.