Introduction to ADO Net and VS Database Tools

Introduction to ADO. Net and VS Database Tools and Data Binding ISYS 350

Client/Server Structure a. Presentation – user interface • Menus, forms, reports, etc b. Processing logic • Business rules c. Database SQL queries Client Database Server Results

Database Processing • Querying database • Updating database: – Insertion, deletion, modification

Steps to Retrieve Data • Establishes a connection to the database. • Executes commands against the database. • Store data results.

A Simplified View of ADO. Net Objects Ado. Net Data Provider Adapter Connection Dataset SQL Updates Command Reader Data Consumer Win. Form Web. Form Results of SQL Selects

ADO. NET Objects • Connection Object: Represent a connection to the database. • Command Object: The command object allows us to execute a SQL statement or a stored procedure. • Data. Reader: It is a read-only and forward-only pointer into a table to retrieve records. • Data. Set Object: A Data. Set object can hold several tables and relationships between tables. • Data. Adapter: This the object used to pass data between the database and the dataset.

Data Providers • ODBC Provider – Open Database Connectivity • A driver manager • Used for relational databases • OLE DB Provider – OLE DB interfaces provide applications with uniform access to data stored in diverse information sources, or data stores. – Access • SQL Server Provider • Oracle Provider – Microsoft’s. NET data provider for Oracle • Etc.

Using ODBC • Windows 7: • Control Panel /Administrative Tools/Data. Source(ODBC) • Three types of data source names – User DSN: usable only by you and only on the machine currently using. – System DSN: Any one using the machine can use. – File DSN: Can be copied and used by other computers with the same driver installed. • Demo: – Excel: Data/Get External Data/From other sources – Access: File/Get External Data/Import, then select ODBC data source • Note: For 32 bit software, you have to open the ODBC panel from C: WindowsSys. WOW 64odbcad 32. exe

VS Database Tools • Add a new connection to database: – Database connection: • Tools/Connect to database – Add Connection – Server Explorer • Data connections: Right click data connection – Add Connection » Tables, Views • Create new SQL Server Database • Add a new data source: – Data/Add New Data Source – Data/Show Data Source

Adding Data Source to C# Project • Data/Add New Data Source – Database: • Using the connections – Service – Object

How to create ADO. Net objects? • Automatically generated when creating data bound form. – Form wizard • Using Data Adapter Wizard • Using code: – Example: – dim str. Conn as string ="Provider=Microsoft. Jet. OLEDB. 4. 0; Data Source = c: sales 2 k. mdb" – dim obj. Conn as new Oledb. Connection(str. Conn) – obj. Conn. open()

Data Binding • Connect a control or property to one or more data elements. • Simple binding: Use simple binding to display a field value in controls that show Data Bindings in the property window, such as text box or label. • Complex binding: Use complex binding to bind more than one field to controls such as Data. Grid and list box. Use the control’s Data Source and Data Member to bind the data.

Creating Data Bound Form • Creating a form with ADO. Net objects and databound controls to display and update information in a dataset. • Demo: – Add data source: • Data/Add New Data Source • Data/Show Data Source – Click the dropdown list next to the table’s name: • Datagrid view • Details – Drag the table to form.

Items Added to the Form • Table Adapter: click smart tag – Add query – Preview data • Dataset: – Edit in dataset designer • Binding Source – Add query: Add a new tool strip. – Preview data • Binding navigator • Code view: Form load event

Other Data Form Demos • Data. Grid View • Add /Modify/Delete records. • Read only form: – Delete Add. New, Delete, Save buttons from navigator bar.

Hierarchical Forms • Parent table/Child table – Add parent table and child table to Data Source – Drag the parent table and the child table to the form. Parent table uses detail view and child table uses data. Grid view – Right. Click Dataset object to choose Edit in Dataset Designer – With the designer, right click the parent table and choose Add/Relation – Change data. Grid’s Data. Source property to the relation.

Detail Form with Bound List. Box • Example: Customer table form with CID listbox and displays selected customer information in textboxes. – Choose detail view for the customer table. – Click the dropdown list next to the CID field and click List. Box – Drag the Customer table to the form. – Bind the CID field to the Binding. Source: • Activate the Property window and click the listbox • Set the Data. SOurce property to Binding. Source • Set the Display Member property to CID

Creating A Database Application Without Programming • Creating a database application to display information and update database. • A main form with buttons to open data forms: – Display. Info – Enter New – Modify – Exit

Form • Form is defined as a class. • Methods: – – To open a form: Show, Show. Dialog Activate, Focus: Make an opened form get focus Hide, Close Ex. • this. Hide(), this. Close() • Events: – Load, Activated, De. Activate, Closing, Closed

• Modeless form: Other forms can receive input focus while this form remains active. – Form. Name. Show() • Modal form: No other form can receive focus while this form remains active. – Form. Name. Show. Dialog()

Multiple Forms Two forms: Form 1, Form 2 To Open Form 2 from Form 1: Standard but troublesome way to open a form: Must create an instance of the form class by using the keyword New to access the form. Form 2 f 2 = new Form 2 (); Open Form 2 as a Modeless form: f 2. Show (); Open Form 2 as a Modal form: f 2. Show. Dialog(); Demo: Problem with the Show method