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ASP.NET Web Pages - Databases

This chapter is about working with databases.

What We Will Do

In this chapter we will:

  • Create a web page to list data from a database

Displaying Data from Database

With Web Pages, you can easily display data from a database.

You can connect to an existing database, or create a new database from scratch.

In this example we will connect to an existing SQL Server Compact database.

Adding a Customers Page

In the "DemoWebPages" folder, create a new CSHTML file named "Products.cshtml".

Replace the code in the file with the code from the example below:

Products.cshtml

@{
var db = Database.Open("SmallBakery"); 
var selectQueryString = "SELECT * FROM Product ORDER BY Name"; 
}
<html> 
<body> 
<h1>Small Bakery Products</h1> 
<table> 
<tr>
<th>Id</th> 
<th>Product</th> 
<th>Description</th> 
<th>Price</th> 
</tr>
@foreach(var row in db.Query(selectQueryString))
{
<tr> 
<td>@row.Id</td> 
<td>@row.Name</td> 
<td>@row.Description</td> 
<td align="right">@row.Price</td> 
</tr> 
}
</table> 
</body> 
</html>

Example Explained

The Database.Open(name) method will connect to a database in two steps:

First, it searches the application's App_Data folder for a database that matches the name parameter without the file-name extension.

If no file is found, it looks for a "connection string" in the application's Web.config file.

(A connection string contains information about how to connect to a database. It can include a file path, or the name of an SQL database, with full user name and password)

This two-step search makes it possible to test the application with a local database, and run the application on a web host using a connection string.

ASP.NET Database Object Reference

Method

Description

Database.Execute(SQLstatement [, parameters])

Executes SQLstatement (with optional parameters) such as INSERT, DELETE, or UPDATE and returns a count of affected records.

Database.GetLastInsertId()

Returns the identity column from the most recently inserted row.

Database.Open(filename)
Database.Open(connectionStringName)

Opens either the specified database file or the database specified using a named connection string from the Web.config file.

Database.OpenConnectionString(connectionString)

Opens a database using the connection string. (This contrasts with Database.Open, which uses a connection string name.)

Database.Query(SQLstatement[, parameters])

Queries the database using SQLstatement (optionally passing parameters) and returns the results as a collection.

Database.QuerySingle(SQLstatement [, parameters])

Executes SQLstatement (with optional parameters) and returns a single record.

Database.QueryValue(SQLstatement [, parameters])

Executes SQLstatement (with optional parameters) and returns a single value.

 

WebPages Databases
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