Structure Query Language (SQL)

The Structured Query Language (SQL) is a standard database language for creating, maintaining, and retrieving relational databases. Edgar F. Codd’s relational paradigm was used in one of the earliest commercial languages, SQL. In his influential 1970 work, “A Relational Approach of Data for Large Shared Data Banks,” he described the model. Despite not following strictly Codd’s relational paradigm, it became the most extensively used database language. Relational algebra was introduced by Codd and is used to define relationships between data tables. SQL’s theoretical base is this. Donald Chamberlin and Raymond Boyce, two IBM researchers, created the first SQL implementation. In 1986, the American National Standards Institute (ANSI) approved SQL as a standard, and in 1987, the International Organization for Standardization (ISO) approved it. The standard has since been updated to incorporate a broader range of functions. Despite the availability of standards, most SQL code must be modified in some way before it can be ported to multiple database systems.

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The following are some interesting SQL facts:

  • SQL does not care about the case.
  • However, it is advised that keywords (such as SELECT, UPDATE, CREATE, and so on) be written in capital letters, while user-defined items (such as table names, column names, and so on) be written in small characters.
  • In SQL, we can use the “–” (double hyphen) at the beginning of any line to create comments.
  • SQL is the programming language for relational databases such as MySQL, Oracle, Sybase, SQL Server, Postgre, and others.
  • MongoDB, DynamoDB, and other non-relational databases (commonly known as NoSQL) do not employ SQL.
  • Even though SQL is an ISO standard, most implementations have subtle differences in syntax.
  • As a result, we may come across queries that operate in SQL Server but not in MySQL.

There are three major types of query languages in modern SQL. Each language relates to one of the functions or tasks. All three come together to make a completely functional language that allows a user to execute all of the functions that can be performed on a relational database.

  • Schema: To create tables and define relationships between them, Schema Query Language (SchemaQL) is utilized. The ‘CREATE TABLE’ statement is the most popular SchemaQL example.
  • Transact: The ability to insert, update, and delete data in a relational database is provided by transacting SQL.
  • Data: The part that interacts with stored data is the data query language. This makes it possible for users to query the data and perform data analysis.

What is SQL: Relational Databases

A baseline understanding of relational databases is required in addition to the previously provided information. A relational database is a type of database in which linked data is stored in numerous tables. It allows users to simultaneously query or request data from many tables.

Consider a company that wants to keep track of its sales or customer information. An Excel spreadsheet may appear to be a sensible concept at first. Information such as the date of the order placement, the order number, the customer’s name, address and other contact information, the amount payable, and so on can be segregated into columns.

As your customer base grows and your business expands, a simple database will become unwieldy, unmanageable, and redundant. Users will run into issues with repeat orders and data entries, which add unneeded duplication and take up more space than necessary. As the system grows, it becomes increasingly inefficient.

Data integrity issues also plague basic data entry systems. Users can not be certain that every entry field is assigned the correct data type or that the entry system is uniform. SQL and relational databases were created to address the mentioned problems and elevate database management to a new level.

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What is SQL Used For?

For a variety of reasons, SQL is used by millions of developers all around the world. It has a broad range of characteristics, including the following:

  • As previously explained, it allows users to access, define, manipulate, and manage data in RMDBSs.
  • It allows users to build and delete tables, databases, tables, views, and procedures, as well as establish permissions on tables, views, and procedures.
  • Users can construct numerous functionalities within a database, such as views and stored procedures.
  • It uses SQL modules, pre-compilers, and libraries to allow users to embed data into other languages.
  • SQL is competent in running queries against a database.
  • It can be used to get data from a database.
  • It can be used to create new records in a database.
  • SQL can build new databases.
  • It can create new tables in a database.
  • SQL can create stored procedures in a database.
  • SQL can be used to generate views in a database,

What are SQL – Commands, and Sub-Languages

Understanding the basic SQL commands will give users a better understanding of what SQL is and how it is utilized. “CREATE,” “SELECT,” “INSERT,” “UPDATE,” “DROP,” and “DELETE” are the most fundamental commands required to communicate with relational databases.

DDL – Data Definition Language

“CREATE,” “ALTER,” and “DROP” are among the categories. Programmers can use these commands to build, change, or alter database objects, such as tables.

CREATE — Creates a new table, view of a table, or another database object.

ALTER — Modifies a database item currently in use.

DROP — Removes or deletes a table view, an entire table, or database objects.

DML – Data Manipulation Language

The commands in this category are used to store and modify data in a database.

SELECT — Retrieves data from a single or many tables.

INSERT — This command creates a new record in the database.

UPDATE – Make changes to records.

DELETE — Deletes data.

DCL – Data Control Language

When users want to set access limits for the database, users utilize the DCL sub-language.

GRANT – Gives a user permission to do something.

REVOKE – This command is used to revoke a previously granted privilege.

TCL – Transaction Control Language

This classification helps to manage changes made by DML commands.

COMMIT — This command ends a current transaction and lets users make any changes made during it permanent.

ROLLBACK is the polar opposite of “COMMIT.” It allows users to send a transaction, but all changes made during that transaction will be undone.


  • Apart from understanding what SQL is used for, SQL’s importance in a programmer’s skill set can be stated as follows:
  • It’s simple to grasp. Because its syntax is similar to logical English sentences, users can grasp it more easily as a query language rather than a programming language.
  • It provides users with a clearer picture of your data (s).
  • It does not change much because it is an ISO standard language.
  • Users won’t have to worry about too many upgrades once they user has mastered SQL, and the user will have a talent that can use for a long time.
  • Much superior to Excel. When compared to normal spreadsheets, SQL allows the user to manage significantly larger (even huge) datasets.

Blockchain or Relational Databases?

We have been accustomed to keeping data in a centralized fashion for decades. Large multinational corporations hold vast volumes of global data, providing them with a huge competitive advantage. Developers are using block chain to move data away from centralization. They are either challenging the concept of centralized databases or providing a feasible alternative to the existing paradigm.

Data storage is becoming decentralized and disintermediated due to block chain technology, with many copies of databases maintained on various computers around the world. We are no longer bound by the opaque, monolithic culture that surrounds Web2 databases.

Block chain and Web3 are giving us new choices and altering the way we save, host, manage and access our data. The infrastructure selection should be based on company goals, resources, capabilities, and preferences. Block chains provide a dependable, decentralized, and fault-tolerant method of storing and retrieving data. Relational databases, on the other hand, provide performance advantages as well as a clear advantage in terms of deployment ease, as they do not require the node and backend infrastructure that Ethereum and other block chains have.

Users should also think about where these technologies intersect. Smart contracts exist as “stored procedures” on relational databases, and hybrid projects can use both types of databases.

SQL in Block chain Development

Block chain and relational databases, as previously said, have distinct advantages. In theory, at least. In practice, the options are rarely black and white. Because block chains lack querying capabilities, the most practical solution is to incorporate block chain elements into a standard database. As the network expands and more nodes are added, network traffic can increase dramatically without corresponding increases in throughput, capacity, or latency. This can lead to a slew of problems. As a solution, users can build a multi-layered architecture that uses a computer or database interface to transact data and is supported by block chains.

Cassandra, ChainifyDB, CovenantSQL, Post chain, BigChainDB, Modex BCDB, and other projects use a standard interface over the block chain framework. Another intriguing example of this hybrid-layered technique is Aergo. It makes use of SQL smart contracts to build a platform that allows businesses to write and execute smart contracts in commercial settings.

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