Column limitations limit the types of data that can be entered into a column. Although the data in each individual column does not have to be unique, the combination of data in the PRIMARY KEY columns of a specific table must be unique.
In MySQL, the syntax for defining a unique constraint with an ALTER TABLE statement is: TABLE CHANGE constraint name UNIQUE (column1, column2,... column n); table name ADD CONSTRAINT constraint name UNIQUE (column1, column2,... column n); table name.
SQL constraints are rules that a table's data must follow. The type of data that can be entered into a table is limited by constraints. This ensures that the data in the table is accurate and reliable. The action is cancelled if there is a conflict between the constraint and the data action.
SQL constraints are guidelines for how data in a table should be handled. The type of data that can be put into a table is limited by constraints. This guarantees the table's data's accuracy and consistency. The data action is cancelled if there is a conflict between the constraint and the data action.
In SQL, the CHECK constraint is an example of an integrity constraint. The CHECK constraint sets a search criteria that will be used to verify the value entered into a row. If the result of a search condition is FALSE for any row of the table, the constraint is broken (but not if result is UNKNOWN or TRUE).
The course is designed very well and all concepts were explained properly with examples
DURGESH LAL KAVI
Omkar kiran shinde
wonderful to learn from all the teachers. keep up the good work. Thank you
Vinod Kumar Kulkarni
Very useful session for professionals and students.
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EASY TO UNDERSTAND IN OUR OWN LANGUAGE
Thank you so much Meet Shah Sir , It was really great and easy to understand I had clear my doubts in your study. thanks' again ...
Abhijeet Anil Waghmare
This MySQL Database course is really helps you for beginner level. Almost all the basic concepts clear in that course in very simple ways. I strongly recommend this course.