In comparing relational and non-relational databases, it’s crucial to recognize that they can be used for their own purposes. However, they have distinct reasons and uses. A particular type of database isn’t superior to the other as both databases have their place, whether relational or non-relational.
This post aims to explain what a relational database is and what a non-relational one is and conclude with the main characteristics of the various types of databases to assist you in deciding the one that best meets your needs.
Are they relational databases
The term “relational database” refers to a relationship-based database, also known as Relational Database Management System (RDBMS) or SQL database contains rows and tables of data often referred to as records. The word “relational database” was first utilized in 1970, when E.F. Codd coined it at IBM in the research document “A Relational Model of Data for Large Shared Data Banks.” Previously, the most used relational databases were Microsoft SQL Server, Oracle Database, MySQL, and IBM DB2. Several versions free of RDBMS systems have gained popularity throughout the years, including SQL Server Express, PostgreSQL, SQLite, MySQL, and MariaDB.
A relational database connects data across multiple tables using ” keys.” Keys are unique identifiers assigned to a particular row of data in the table. This unique identifier is referred to as”a ” primary key” and is then added to a record in a different table, provided that the record is linked with the main record of the primary table. Suppose this unique primary number is added to a record of another table. In that case, it’s described as”a ” foreign key” in the table it is associated with. The link between the primary key and foreign keys then establishes”the ” relationship” between the records in multiple tables.
This image shows the primary/foreign keys relationship between two tables. The Employees table has only one row describing an employee. Each employee has been assigned a unique ID (primary key). In this instance, it is referred to as EmployeeId. Another table called Sales has individual sales records that can be linked to the person who was the one who made the sale. Since an employee may sell multiple times, the unique EmployeeID (primary key) could appear in the sales table as a foreign key in several instances.
Benefits of referential databases
The primary benefit of using the RDBMS is “referential integrity.” Referential integrity refers to the reliability and reliability of the data. Data integrity can be achieved through the primary keys and foreign keys.
Referential integrity protects the integrity of data by using “constraints.” Constraints are the rules to ensure data accuracy by preventing an associated record from being deleted before eliminating the primary form from the preceding table. If a direct foreign critical relationship has been correctly added when removing the prior record without first destroying related documents from other tables will impede the operation until the associated descriptions are eliminated. This will prevent what’s referred to as “orphaned records,” which are those referenced in the table that do not have primary documents in the preceding table.
Which are the three principles for referential integrity
The three guidelines that guarantee referential integrity are:
A foreign key must be paired with a primary key that is identical to it. (“No orphans” rule.)
If a record from a primary table gets deleted, all the documents related to that primary key must also be deleted. This is usually done by making use of cascade delete.
When the key used for individual records changes, all records in the other tables with this primary key for foreign keys also need to be changed. This can be done by making use of the cascade update.
Queries in the database
The process of querying data of a management database that uses a relational model is accomplished through Structured Querying Language (SQL), a potent language specifically designed to manage the information stored in the database.
SQL can make, read, edit, and erase records. It heavily relies on this primary/foreign relationship to distinguish related data across several tables. Its features SQL provide the system with the ability to be the ideal option for any task requiring solid transactional capability, data mining, and sophisticated reporting.
This SQL statement illustrates retrieving a result set of all sales records of a single employee whose EmployeeId will be found. The following SQL statement provides an example of using joins to multiple tables. In this particular instance, the SQL query will retrieve all employee data, sales data, and information about customers from the table Customers.
The functionality of relational databases is that is known as “indexing.” A database index is a data structure that speeds up data retrieval. Indexes are typically added to data fields frequently used to query tables or join them. The above SQL statements CompanyId and EmployeeId, are prime potential candidates for this optimization.
Which databases are not relational
The non-relational database, also known as the NoSQL database, is a database that stores information. But, unlike relational databases, it has no rows, tables, primary keys, and foreign keys. Instead, the non-relational database employs an optimized storage model designed to meet the specific requirements for the data storage type.
The most well-known NoSQL databases include MongoDB, Apache Cassandra, Redis, Couchbase, and Apache HBase.
Five types of non-relational database
There are five well-known non-relational types: document information stores, column-oriented databases, key-value stores, document stores, and graph databases. Most often, these types are utilized in one application.
Document data stores
Document data stores manage the named strings and objects with data values in the form of”documents. “document” is typically stored in JSON documents. Various methods may encode them, such as XML, YAML, JSON, BSON, or plain text. The fields contained in documents are visible, allowing applications to query and filter the information using fields.
Document storage does not need all documents to have identical data structures. This allows for a wide range of flexibility. It is easy to understand how this flexibility could be utilized as the company’s needs alter.