SQL Databases, NoSQL Databases, Key-Value Stores, Column-Oriented Databases, Graph Databases, Document Store Databases

This study comprises a research about both SQL and NoSQL databases and a comparison in terms of the advantages and disadvantages of each. The comparison is implemented depending on scalability, (ACID and CAP) theory, flexibility, performance, schema, query language, cost, speed and the stored data. We described briefly several examples of SQL databases including My SQL , MS-SQL Server Express Edition , Oracle 11g Express Edition Database. Also, the study included a description for many types of NoSQL database including Key-Value Store Database, Column-Oriented Database, Document Store Database and Graph Databases. The result of the study detected that SQL database is a table based database, supports flexibility, is vertical scalable, and utilizes Structured Language Query. On the other hand, the study discovered that SQL database is not a suitable choice for hierarchical data storage, etc. Whereas in terms of NoSQL, the study discovered that NoSQL databases are less flexible, however, horizontally scalable, have a non-structured querying language and is a good choice for hierarchical databases.