ASP.NET Database Connectivity 1

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ASP.NET Database Connectivity 1
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Outline

• SQL Review
• ASP.NET Database Connectivity

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Retrieving Data

• SELECT field1, field2,
• FROM tableName
• WHERE conditions
• The SELECT clause lists the fields retrieved in
  the query result, separated by commas
• The FROM clause lists one or more table names to
  be used by the query
• All fields listed in the SELECT or WHERE clauses
  must be found in one and only one of the tables
  listed in the FROM clause

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ltaspGridViewgt

• It provides Excel-like user interface to display
  information from a database
• Syntax
• ltaspGridView id"GridView1" runat"server" /gt
• Attributes
• datasource data source object
• Methods
• Databind() binding the data from the datasource

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ADO.NET

• ADO ActiveX Data Objects
• ADO.NET
• A set of class libraries in the .NET Framework
  that makes it easier to use database
• These classes provide certain functionality
• You can use the classes from VB or C

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ADO.NET
SQL Server
OLE DB
Oracle
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OLEDB

• OLEDB Object Linking and Embedding for Databases
• It can communicate with any database that is
  OLEDB-enabled, such as MySQL, DB2

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Database Engine

• JET, Joint Engine Technology
• A database engine that runs in the background and
  uses MDB (Access) files
• JET accepts commands directly from other software
  such as VB to read or modify MDB files
• ACE (Access Engine) is the new database engine
• It is backward compatible

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Connection Object

• An ADO.NET object that represents a unique path
  between a data user and data provider
• Methods
• open()
• close()

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Command Object

• An ADO.NET object that represents an SQL
  statement that can be passed to a database
• Method
• ExecuteReader()
• Creates a DataReader

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DataReader

• A storage of the data obtained from the database
• Can only read data
• It is discarded at the end of the request

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Six Steps to Connect to a DB

• Create a GridView control in the webpage
• Create a connection object
• Create a string text to hold SQL statement
• Create a command object
• Open connection
• Create DataReader and send data to GridView