Notes on SQL

SQL is a standardised programming language for managing relational databases and performing different operations on the data contained inside them. SQL, which was first developed in the 1970s, is now widely used by database administrators, developers creating data integration scripts, and data analysts setting up and running analytical queries.

SQL is used to perform the following tasks:

• modifying database table and index structures;
• adding, updating, and deleting rows of data; and
• retrieving subsets of information from relational database management systems (RDBMSes) — this information can be used for transaction processing, analytics, and other applications that require communicating with a relational database.

SQL has three subordinate languages:

Data Definition Language (DDL): It contains the following commands:

• To create tables in the database, use the CREATE command.
• To change the existing table structure: ALTER
• To drop a table using a table structure, use the DROP command.
• It is used to insert, remove, update, and query data in these tables using the Data Manipulation Language (DML). The following are some DML commands.
• To put data into a table, use the INSERT command.
• SELECT To get data out of the table.
• UPDATE To update the table’s existing data.
• DELETE is used to erase data from a table.

Data Control Language (DCL): It’s used to limit which users have access to which database items. The following are some of the DCL commands:

• GRANT: Used to grant access to select/insert/delete
• REVOKE: Used to withdraw the supplied access

Transaction Control Language (TCL): It is used to keep track of data changes.

• COMMIT To preserve work done on the table, such as entering, modifying, or removing data.
• ROLLBACK Restores the database to its previous state after a commit.
• SQL Data Types define the types, sizes, and formats of data and information that may be stored in columns and variables.

Advantages of Using SQL:

• Higher Processing Speed: When users browse the database, SQL runs at a high speed. It aids in the retrieval of enormous volumes of data in a timely and effective manner.
• SQL has a low coding requirement since it is extremely user friendly. Basic SQL coding may be learned in a matter of days by someone who has never coded before. The coding structure is relatively straightforward, drawing mainly on English language and employing few special characters.
• Data Manipulation is Easier: SQL makes it incredibly simple to access and manipulate data in a database. Users may update or edit the uploaded information in the database with a few queries, making it useful for storing dynamic data.
• Easier Data Mining: SQL is used for sorting and filtering data using many queries, making the data more relevant and helpful while minimising redundancy, among other things. It is completely employed to manage their database when SQL or MySQL is being used. Anyone who are familiar with SQL will find it easier to browse.
• SQL is generally perceived as a secure and well-protected database. Every device in the system is passcode secured, making it harder for unauthorized users to discover the data without permission.
• When compared to other Database Management systems, SQL is extremely trustworthy when it comes to delivering proper answers on complicated queries by users.

What is IBM Db2 Big SQL?

IBM Db2 Big SQL is a hybrid ANSI-compliant SQL-on-Hadoop engine that supports massively parallel processing (MPP) and complex data queries. Db2 Big SQL allows you to connect to and query several databases at once, including Hadoop HDFS and WebHDFS, RDMS, NoSQL databases, and object stores. To run ad hoc and sophisticated queries, take advantage of low latency, high speed, data security, SQL compatibility, and federation features.

Big SQL for Db2 is now available in two flavours. It may be used in conjunction with Cloudera Data Platform or as a cloud-native service on IBM Cloud Pak for Data.

Big SQL’s features:

• Elastic boost technique allows for more precise resource allocation and improved performance without raising memory or CPU utilisation.
• Scans, inserts, updates, and deletions at high speeds
• Other SQL-on-Hadoop solutions have a deeper integration with Spark 2.1 than other SQL-on-Hadoop technologies.
• With Spark, you can do machine learning or graph analytics with a single security model.
• Advanced, ANSI-compliant SQL queries Open Data Platform initiative (ODPi) compliance

Database:

In SQL Server, a database is made up of a series of tables that each hold a specific set of structured data. A table is composed out of rows, that are also known as records or tuples, and columns, that are also formally known as attributes. Every column in the table is supposed to hold a specific sort of data, such as dates, names, dollar amounts, and numbers.

Frequently asked questions-

What Can SQL do?

• SQL is able to run queries against a database.
• SQL can be used to get data from a database.
• SQL could be used to create new records in a database.
• SQL can be used to modify data in a database.
• SQL has the power to delete records from a database.
• SQL has the capacity to construct new databases.
• SQL has the capability to create new tables in a database.
• In a database, SQL may build stored procedures.
• In a database, SQL may be used to generate views.
• SQL has the ability to assign rights to tables, procedures, and views.

Conclusion:

SQL is a language for interacting with databases. It is the common language for relational database systems, according to ANSI (American National Standards Institute). SQL statements are being used to perform tasks like modifying data in a database and retrieval of data from database. Unlike Excel, SQL can easily manage data with over one million fields. In addition, SQL queries are more versatile and powerful than Excel formula. SQL is used by data analysts to interface with large databases by manipulating data.