What are constraints? What is different types of constraints?

Constraints are allows us to enforce rules in our database. SQL Server supports 6 types of constraints. A Constraint is a property that we can assign to column in table. By assigning constraint property on column we can prevent the users to enter inconsistent of data in columns. We can assign these Constraint properties during the time of creation of table (By Using CREATE TABLE statement) or during the time of changing the existing table structure (By Using ALTER TABLE statement)

Primary Key Constraint
Unique Key Constraint
Foreign Key Constraint
Not Null Constraint
Check Constraint
Default Constraint

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Connected and disconnected architecture in ADO.Net with Example

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HTTPHandler and HTTPModule in ASP.NET

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