Check Constraint in SQL-Server

A check constraint is a rule that identifies acceptable column values for data in a row within a SQL Server table. The CHECK constraint ensures that all values in a column satisfy certain conditions.

Example

We will create an Employee table with Check constraint,

Employee Table contain Employee ID, Name and Age.

We set Check constraint property on Age column. Age should not be less than 18

Create table of Employee as follows.

CREATE TABLE Employee

(

EID INT PRIMARY KEY IDENTITY,

ENAME VARCHAR(100),

EAGE INT

CHECK (EAGE>18)

)

Try to insert the below records

INSERT INTO Employee(ENAME,EAGE)VALUES('ABC',20)

Check Constraint allowed to insert record in to the Employee table.but when we try to insert below record, it will shows an error Message

INSERT INTO Employee(ENAME,EAGE)VALUES('PQR',15)

Msg 547, Level 16, State 0, Line 1

The INSERT statement conflicted with the CHECK constraint "CK__Employee__EAGE__5AEE82B9". The conflict occurred in database "XXXX", table "dbo.Employee", column 'EAGE'.

The statement has been terminated.

Employee Contain only first record

SELECT * FROM Employee

Comments

Connected and disconnected architecture in ADO.Net with Example

Connected Architecture of ADO.NET The architecture of ADO.net, in which connection must be opened to access the data retrieved from database is called as connected architecture. Connected architecture was built on the classes connection, command, datareader and transaction. Connected architecture is when you constantly make trips to the database for any CRUD (Create, Read, Update and Delete) operation you wish to do. This creates more traffic to the database but is normally much faster as you should be doing smaller transactions. Disconnected Architecture in ADO.NET The architecture of ADO.net in which data retrieved from database can be accessed even when connection to database was closed is called as disconnected architecture. Disconnected architecture of ADO.net was built on classes connection, dataadapter, commandbuilder and dataset and dataview. Disconnected architecture is a method of retrieving a r...

ASP.Net AJAX Interview Questions

What is Ajax? Ajax means " Asynchronous Javascript and XM L". Ajax represents a set of commonly used techniques, like HTML/XHTML, CSS, Document Object Model(DOM), XML/XSLT, Javascript and the XMLHttpRequest object, to create RIA's (Rich Internet Applications). ASP.NET AJAX update only a specified portion of data without refreshing the entire page. The ASP.NET AJAX works with the AJAX Library that uses object-oriented programming (OOP) to develop rich Web applications that communicate with the server using asynchronous postback. What are the different controls of ASP.NET AJAX? ASP.NET AJAX includes the following controls: ScriptManager ScriptManagerProxy UpdatePanel UpdateProgress Timer Describe the technology that makes up AJAX? AJAX is based on the following web standards: XMLHttpRequest Object JavaScript HTML/DHTML DOM XML CSS What role does the ScriptManager play? The ScriptManager manages all ASP.Net AJAX resour...

HTTPHandler and HTTPModule in ASP.NET

If you want to implement pre-processing logic before a request hits the IIS resources. For instance you would like to apply security mechanism, URL rewriting, filter something in the request, etc. ASP.NET has provided two types of interception HttpModule and HttpHandler . The web server examines the file name extension of the requested file, and determines which ISAPI extension should handle the request. Then the request is passed to the appropriate ISAPI extension. For Example When an .aspx page is requested it is passed to ASP.Net page handler. Then Application domain is created and after that different ASP.Net objects like Httpcontext, HttpRequest, HttpResponse. HTTPModule: - It's just like a filter. The Modules are called before and after the handler executes . - HTTP Modules are objects which also participate the pipeline but they work before and after the HTTP Handler does its job, and produce additional serv...

Help to understand .Net

Search This Blog