data-mining & data as we used excel that has capability to analyze data to find important...
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Data-mining & Data
• As we used Excel that has capability to analyze data to find important information, the data-mining helps us to extract information from data. However, not all data can be used for that data-mining.
• We need to understand data can be classified into three parts including database, data-warehouse, and data-mart.
• For example, typical retail shop has database that keep track of sales, inventories, and customers. Sales data is used to keep records of sales that customers made such as product, quantity, price, date and so on. Inventory data contains the records of products that this retail shop is currently keeps. It may be name of product, price, maker, and units.
Data-mining and Data
• Database such as sales data can be used for data-mining to find the information such as seasonal sales trends. However, by combining multiple data such as customer data, sales data, and inventory data, more useful information can be obtained with data-mining. To combining data, it necessary to determine the relationship between each data. For instance, particular sales in the sales data is made by a customer in the customer data. This relationship must be clearly defined. The combining multiple data by this kind of relationship is called data-warehouse.
Data-mining and Data
• Not all data in the data-warehouse is necessary for data-mining to analyze. In many case, we need to extract necessary data from data-warehouse for analysis. This extracted data is called data-mart. For instance, only particular customer group such as young adult is needed to analyze their sales pattern.
• Data, data-warehouse, and data-mart is used by many organizations to find important information to make better decisions.
• To construct data, data-warehouse, and data-mart, these organizations use database management system such as Oracle, SQL server, and Access.
Database Management System
• Database is a collection of integrated data items that includes a descriptions of the data therein.
• Database structure means a relational view of database that is a collection of tables in which rows of the table represent records and the columns of the table represent fields or attributes of a record.
Schema
• Schema is a description of complete structure of the database, including names and descriptions of all data items, sets of data, and collections of the data item sets.
• Names assigned in the schema are used to reference individual data items and collections of data items within the database.
Database Structure
• Relational view or structure is a collection of tables in which the rows of each table represent database records, and the columns of each table refer to the fields or attributes of a record.
Order Table OrderItem Table
Record
Field
Basic Structure of Database
Order Table OrderItem TableRecord
Field
Primary Key
Foreign Key Primary Key
Important Terms
• Table
– A logical structure used to group sets of related information
• Record
– A set of attributes describing each person, place, or item in the database
• Field– An attribute of record
• Primary Key– Each record in a relational database must be unique. This is accomplished by assigning a
unique ID or number to each record, which is called primary key.
• Foreign key– Fields in common between tables. It makes possible to link two tables.
• Index– Access to the database record can be faster through the use of index assigned to fields
• Queries– Language used to communicate with database. In VB, English-like language names Structured
Query Language (SQL) is used to retrieve data from a database.
Two Types of Database
• Local database
– It generally used for single-user application.
– Some of commercially available database includes, Microsoft Access, Microsoft FoxPro, dBase, Paradox, and ASCII.
– Visual Basic can access it through Visual Basic’s database Jet engine using Data Access Object.
• Remote Database
– By definition, remote databases don’t reside on the user’s PC. It requires an ODBC (Open Database Connectivity) driver for an application to access it. It can be accessed by multiple applications spontaneously.
– Some of commercially available database include Oracle, Sybase, and Microsoft SQL Server.
– Visual Basic can access it through Remote Data Object and ODBC.
Building MS Access Database
• By using Microsoft Access
• By using Visual Data Manager
Building MS Access Database by using Microsoft Access
• Step 1: Make Database File
• Step 2: Create Tables
• Step 3: Define Relationships
• Step 4: Enter data
Building MS Access Database by using Microsoft Access
Type a name for new Access Database
Step 1: Make Database File
Building MS Access Database by using Microsoft Access
•Step 2: Create Tables Select Tables in the Objects, and double click “Create table in Design View” menu
Design View
Building MS Access Database by using Microsoft Access
Add Columns for the table
Set properties for the column
Design View
Building MS Access Database by using Microsoft Access
• This is sample of designing publisher table
Auto Number data type makes the column having automatic numeric value without user entry. The first record in the table will get value of 1, and subsequent records get incremented value. Hence, every record will have unique value.
Clicking this button in the tool bar makes the current column as primary key of the table
Building MS Access Database by using Microsoft Access
You can change the properties of the column. Here, the field size for the Name column is changed to 100
Building MS Access Database by using Microsoft Access
You need to save table after designing
Click Save button to save table
Building MS Access Database by using Microsoft Access
After designing the table, you can start enter records in the table in Datasheet View. To open Datasheet View click Datasheet button on the Toolbar
Notice Auto Number column where you do not need to type value, Access automatically enter value for new record.
Start enter records
Datasheet View
Building MS Access Database by using Microsoft Access
• Create the second table for Book Title and create relationship with the Publisher table
Each book title is published by specific publisher, so the Book Title table has Publ ID column that holds the key value of Publisher table. To make this relationship, choose Lookup Wizard in the data type.
Lookup Wizard
Click Next
Building MS Access Database by using Microsoft Access
Select Lookup Table Select Lookup Column Choose sort order for Look up column
Lookup Wizard create relationships for two tables
Building MS Access Database by using Microsoft Access
When entering records, you do not need to enter value. Instead, you can choose one from dropdown combo box.
Accessing Database Tables with Relationship from VB
• Using Connection, Data Adapter, and Dataset objects
– To access data from tables with relationship is the same as accessing data from a single table except you must include tables in the Query Builder when creating Data Adopter.