Sometimes we don’t have unique identifiers in the table to create a primary key. In this case, we can take help from SQL to have a special column for the primary key, whose values will be automatically incremented when a new row is inserted. SQL Auto Increment SQL Auto-increment generates a unique incrementing number when […]
SQL Foreign Key
When a database table is designed an important factor is to make sure that the table is scalable enough and is normalized at the same time. In order to make sure that the tables are well linked and normalized we use SQL foreign keys. SQL Foreign Key A foreign key is defined by a column […]
SQL Composite Key
In a real-time situation, there can be scenarios when one column is not good enough to uniquely identify a row. In such scenarios, we use a combination of columns to uniquely identify a row. SQL Composite Key SQL composite key is a combination of two or more columns in a table that is used to […]
SQL Primary Key
In a world driven with data all over, it is very easy to get duplicate data. The nightmare of any database table designer is to create a table with the possibility of duplicate data insertion. To overcome the problem of duplicate rows, SQL primary key is used to uniquely identify each row. SQL Primary Key […]
SQL Constraints
In a real-world scenario, there are cases when we would like to restrict the type of data that is getting stored in the DB table. In order to achieve the restriction on the database, SQL provides a set of constraints. Introduction SQL constraints are a set of rules that are used for restricting the data […]
SQL Temp Table
In real time scenario, consider that you have read-only access on a table and you have to manipulate some data in it. It is always useful to create a temp table when you want to use the table in the current session. Introduction In this tutorial, we will discuss the temporary table in MySQL. Following […]
SQL Copy Table
In real time we do face situations where we need to copy data from one table to another table or when we need to create a table from a set of data from the table. We will discuss in this article the solution for such cases. SQL Copy Table Creating a backup table is very […]
SQL Truncate Table
SQL Truncate Table Assume a case when we want to have the database but we would like to delete the data of the table. In such cases, TRUNCATE command is used to delete just the data from the table. The table structure will remain as it is. Syntax for SQL TRUNCATE TRUNCATE TABLE <table_name>; We […]
SQL ALTER Table
We have discussed how to create a table in the database, but there are cases when we would like to modify the table that was created. In order to modify a table SQL provides ALTER as the keyword. We will try to understand the usage of the ALTER keyword for altering a table in detail. […]
SQL Drop Table
In a real-time situation, there are scenarios when we would like to remove the table from the database. Let us discuss in detail about the process of removing a table from the database. SQL DROP TABLE The SQL DROP TABLE statement informs the database that a particular table needs to be removed. SQL DROP TABLE […]