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What is TCL? Transactional control commands(TCL) can only be used with DML commands like INSERT, UPDATE, and DELETE. They cannot be used when creating or deleting tables because the database automatically commits these operations. NOTE: Before proceeding with TCL commands, you must know about the DML & DDL commands. COMMIT command: The Commit command is used […]
March 22, 2023 | DBMS | No comments
What is Delete Query? In SQL, the DELETE Query removes existing records from a table. Depending on the condition specified in the WHERE clause, we can delete a single record or multiple records. NOTE: This command must be used with extreme caution because it permanently deletes the data. Syntax: where table_name is the table that has […]
March 22, 2023 | DBMS | No comments
What is an UPDATE QUERY? The SQL UPDATE statement is used to modify the data in tables’ records. A condition determines which rows are to be updated. The WHERE clause is used to specify conditions. Syntax: where, table_name: name of the table column_name: name of first, second, third column… expression: new value for first, second, […]
March 17, 2023 | DBMS | No comments
Insert is a commonly used command in the Structured Query Language (SQL) data manipulation language (DML) used by SQL Server and Oracle relational databases. The insert command inserts one or more rows into a database table with the specified table column values. The insert statement is the first DML command executed immediately after creating a […]
March 16, 2023 | DBMS | No comments
The various DDL commands that are used to redefine the tables will be covered in this tutorial. Truncate Query: TRUNCATE statement is a Data Definition Language (DDL) operation that is used to mark the extent of a table for deallocation (empty for reuse). This method instantly deletes all of the data from a table while […]
March 15, 2023 | DBMS | No comments
The ALTER command is a DDL command that can be used to change the structure of existing tables in the database by adding, modifying, renaming, or removing columns and constraints. Using the ALTER command, you can add columns, rename columns, delete columns, or change the data type of columns. ALTER Command: Syntax Adding a Column: […]
March 14, 2023 | DBMS | No comments
SQL Data Types are an important component of the attributes present in the tables, as well as the queries used to retrieve data from those tables. SQL data types define attributes based on the categories to which they belong. Data types are mainly classified into three categories for every database. String Data types Numeric Data […]
March 12, 2023 | DBMS | No comments
The SQL CREATE command is a type of DDL command that is primarily used for creating databases and tables. To create databases or tables with the desired structure, the CREATE command has a specific syntax that must be followed.Before we can perform any other functions, we must first create a database, which is the first […]
March 12, 2023 | DBMS | No comments
A programming language called SQL (Structured Query Language) was created specifically for managing and modifying relational databases. It offers a common syntax for entering queries and making changes to data in databases. SQL was the first commercial language introduced for E.F Codd’s Relational model of a database. Note: The programming language SQL was created specifically for managing […]
March 12, 2023 | DBMS | No comments
What is 5NF? The fifth normal form, or 5NF, is also called the project-join normal form. If a relation is in 4NF and does not have lossless decomposition into smaller tables, it is in Fifth Normal Form (5NF). If redundancy is avoided, 5NF is satisfied when all tables are divided into as many tables as […]
March 12, 2023 | DBMS | No comments