Difference between revisions of "DD Advanced ADO"

Latest revision as of 03:23, 9 February 2016

Review ADO

• Connection - used to connect the data consumer ASP.NEt to a Data Provider
• Command - used to issue SQL commands to a Data Provider
• DataReader - A fast forward only DataSet that holds one or more resultsets.Fast and efficient
• DataSet - can contain multiple tables and relationships between tables
• DataAdapter - Passes Data from a Connection object to a DataSet and updates that data. ( A bridge used to fill dataSets with DataAdapter.Fill and DataAdapter.Update)
• DataTable - structure that holds a set of rows and columns
• DataRelation - holds relations between DataTables in a DataSet
• DataRow - data within data row
• DataView - a specific view of the DataTables within a Dataset

Template:ADO.NET Diagram

Simple ADO Binding

//Connection string comes from web config
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["IamConnectionJeff"].ConnectionString);             
        
        string strSQL = "Select * from Course";  
        
        SqlCommand dc = new SqlCommand(strSQL , conn);
        SqlDataAdapter da = new SqlDataAdapter(dc);
        DataSet ds = new DataSet();
        DataTable dt = new DataTable();
        
        da.Fill(ds, "Course");          //Use the DataAdapter to fill the DataSet with a named Table
        dt = ds.Tables["Course"];       //Retreive the named table from the DataSet
        
        gvTestOrig.DataSource = dt;     //Set the DataTable as the source for the GridView noe AutoGenerateColumns = true
        gvTestOrig.DataBind();          //Bind the data form the table to the GridView

The above code binds to a control called gvTestOrig

 <asp:GridView ID="gvTestOrig" runat="server" AutoGenerateColumns="true" />

http://iam.colum.edu/dd/classsource/class8/SimpleADO.aspx - source

Same code but I moved some of the code into a function and split the declareation and initialization of some object to that they are scoped to the page not to Page_Load. This allows other functions on the page to use these objects.

http://iam.colum.edu/dd/classsource/class8/ADOTest1.aspx - source

Inserting Editing Deleteing With ADO

Add to a DataTable

        DataTable dt = ds.Tables["Course"];
        DataRow dr = dt.NewRow();
        dr["CourseName"] = "Applcations Design";
        dr["CourseNumber"] = "36-3601";
        dt.Rows.Add(dr);

Modify and DataTable

        DataTable dt = ds.Tables["Course"];
        DataRow dr = dt.Rows[3];            //Hack hard coded index
        dr["CourseName"] = "Application Design";
        dr["CourseNumber"] = "36-4601";

Delete from a DataTable

        DataTable dt = ds.Tables["Course"];
        DataRow dr = dt.Rows[1];            //Hack hard coded index
        dt.Rows.Remove(dr);

There are better method to select which row to modify see the example below

http://iam.colum.edu/dd/classsource/class8/ADOTest2AddModifyDelete.aspx - source

notice that changes made to the DataSet are not synchronized back to the Data Provider. 
The DataAdapter is able to sync these changes, remeber that the DataAdapter acts as a bridge between the 
DataSet and the DataProvider.

The DataAdapter can use the SqlStringBuilder class to create select, update, and delete statements. Once these statements are built the DataAdapter can update the DataProvider.

//Uses an SqlBuilder to update the DataAdapter also displays the generated sql in a lable
    public void CommitChanges()
    {
        //Get a stringBuilder from out DataAdapter
        SqlCommandBuilder cb = new SqlCommandBuilder(da);
        da.UpdateCommand = cb.GetUpdateCommand();
        lblUpdateCommand.Text = da.UpdateCommand.CommandText;   //Display the update Command in a Label
        da.Update(ds.Tables["Course"]);         //User tha DataAdpater to update the Data Provider
    }

http://iam.colum.edu/dd/classsource/class8/ADOTest3Commit.aspx - source

Homework

1 Build a page that demonstrates a single table update with ADO,

2 Write a proposal for final project the proposal should include

Proposal Template: http://iam.colum.edu/janell/edu/wi/docs/proposal_wi.rtf

Proposal Template (pdf): http://iam.colum.edu/janell/edu/wi/docs/proposal_wi.pdf

• Purpose
• Objectives
• Audience

• Website Scope
  • Simple map of web site(can be on paper or hyperlinks)
  • Number of web pages
  • Function of web pages
• DataBase Design
  • Mock up of tables and relations
  • ERD on paper or diagram in sql