Databases - C Sharp Programming - Lecture Slides, Slides of C programming

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Databases

14_databases.ppt

Overview of Topics

• Relational Database Terminology

• ADO.Net

• Binding data

Database Terminology

• A database is made up of one or more related tables.
• Conceptually a table is made up of rows and columns (2D Array).
• Each row represents the data for one record (a person, inventory item, course information).
• Each column (field) is a data element (name, address, city, state, zip).
• Tables have a Primary Key Field to uniquely identify each record (Id number, part number, account number).
• Relationships between various tables can be defined.
• A DBMS stores everything (tables, columns, relationships, etc.) about the database in system tables.
• System and data tables are usually stored in one file (CSMail.mbd).

SQL – Structured Query Language

• SQL is pronounced sequel.

• SQL – Structured Query Language – Basic set of

commands that are common in all DBMS.

• DBMS vendors may add additional commands.
• SQL commands are usually processed against a record set.
  • Select name, address From customer where zip = “85202”;
  • Delete From customer where zip = “85202” All rows matching the criteria would be selected or deleted.
  • Record set commands are very powerful.
• We’ll usually want to qualified a command by specifying a

customer id or other unique identifier using the Where clause.

C# Application Reading Database

Accessing a Database – ADO.Net

• Use ActiveX Data Objects (ADO)
• An Access database uses the following objects:
  • OleDbConnection – connection tool establishes a link to a data source.
  • OleDbDataAdapter – data adapter handles retrieving and updating the data and creates a Dataset.
  • Dataset – bind columns in the Dataset to controls (textbox, listbox) by setting the DataBinding property.
  • Use the Fill method of the data adapter to load the data into the dataset, daCustomer.Fill(dsCustomer1); The Fill method is usually placed in the form load event.

Data Binding

• Complex Binding
  • Connect more than one data element to a control.
  • DataGridView uses complex binding because several columns from the table are displayed in the same control.
• Simple Binding
  • Connect one data element to a control.
  • Connect a textbox to the name column (etc.)
  • May use Data Bindings property and select the column from the database that should be displayed in control.
  • Later we’ll build a form using Labels and Textboxes.

Completing CS

• See assignment sheet for details.