Almost all new data created today is digital Problem: How to organize the data and store it? Capacity Speed Life of the data Number of users

Transcription

1 Databases

2 Almost all new data created today is digital Problem: How to organize the data and store it? Capacity Speed Life of the data Number of users 2

3 Batch Processing Transactions are collected over time, and processed all at once Examples: Credit Card bills Utilities bills Real-Time Processing All transactions are processed immediately Examples: ATM withdrawals 3

4 Reasons for their existence Sharing data Security and Authorization Less redundant data Reduces integrity issues Online transactions Audit 4

5 Database integrated collection of related tables Table collection of similar datasets conforming to a template Record (Entity) individual entry in a table Field individual attribute of a record Key field (primary key) attribute that can uniquely indentify individual records in a table 5

6 Programs that work with structured data Employee records, purchase records, student information, etc. Provide capability for creating databases, tables, records, and entries Most provide the ability to present the data in a variety of ways (reports, graphs, etc.) Examples MS Access, MS SQL Server, MySQL, Oracle 6

7 Most of the actual data is stored as binary data (sometimes plaintext) DBMS takes the data, processes it and integrates it into the program Database is manipulated with a programming language called SQL Structured Query Language Lets you access and manipulate databases Is an ANSI (American National Standards Institute) standard 7

8 Create new databases Create new tables in a database Insert records in a database Update records in a database Delete records from a database Retrieve data from a database Execute queries against a database Create stored procedures in a database Create views in a database Set permissions on tables, procedures, and views 8

9 CREATE TABLE INSERT UPDATE DELETE DELETE TABLE SELECT SQL Clauses WHERE FROM 9

10 Syntax CREATE TABLE table_name( column_name1 data_type, column_name2 data_type, column_name3 data_type, ); Example CREATE TABLE student ( first_name VARCHAR (200), last_name VARCHAR (200), id VARCHAR (10), class_level VARCHAR (2) ); Explanation Create a student table to hold a first name, last name, id, and class level. 10

11 Syntax INSERT INTO table_name (column1, column2,...) VALUES (value1, value2,...); Example INSERT INTO student (first_name, last_name, id, class_level) VALUES ("tommy", "trojan", " ", "U1"); Explanation Insert a student named Tommy Trojan with an id of and a class level of U1 (1 st year undergrad) 11

12 Syntax UPDATE table_name SET column1=value, column2=value2, WHERE some_column=some_value; Example UPDATE student SET class_level="u2" WHERE id=" "; Explanation Update the class level to U2 (2 nd year undergraduate) for the student with the id of

13 Syntax DELETE FROM table_name WHERE some_column=some_value; Example DELETE * FROM student; Explanation Delete all of the entries from the student table 13

14 Syntax SELECT column_name(s) FROM table_name WHERE some_column=some_value; Example SELECT first_name, last_name FROM student WHERE class_level="u1" Explanation Return the names of the students who are freshman In MS Access, we create and run reports Creating SELECT commands on the backend 14

15 Data is stored in independent tables and records Data from different tables can be linked using foreign keys (keys from other tables) In Access, you create relationships between tables Entries can be quickly added, modified, and deleted Most common form of databases used today Database relationships are associations between tables 15

16 One-to-one: Both tables can have only one record on either side of the relationship Each primary key value relates to only one (or no) record in the related table They're like spouses Both you and your spouse have only one spouse Most are forced by business rules One-to-many: The primary key table contains only one record that relates to none, one, or many records in the related table This relationship is similar to parent/child One parent may have several children Many-to-many: Each record in both tables can relate to any number of records (or no records) in the other table This is similar to siblings Each sibling can have several siblings Many require a third table, known as an associate or linking table 16

17 CoffeeTable CoffeeID Name Price CoffeeDetailTable CoffeeID Roast Taste Organic CoffeeID Name Price 1 Finca El Jordan 7.99 CoffeeID Roast Taste Organic 1 Light Nutty Yes 2 Dark Rich Yes Single record in one table connects to single record in other table 17

18 SupplierTable SupplierID Name CoffeeTable CoffeeID Name SupplierID SupplierID Name 32 Stumptown 45 Starbucks CoffeeID Name SupplierID 1 Finca 32 1 El Jordan 32 2 Veranda 45 Single record in one table connects to multiple records in other table 18

19 RegionTable RegionID Name ProductsTable CoffeeID RegionID CoffeeTable CoffeeID Name RegionID Name 430 Africa 540 Panama RegionID CoffeeID CoffeeID Name 1 Finca 2 El Jordan 3 Veranda Multiple records in one table connects to multiple records in other table (requires linking table as shown) 19

20 To build a web site that shows some data from a database, you will need the following: An RDBMS database program (i.e. MS Access, SQL Server, MySQL) A server-side scripting language, like PHP or ASP SQL HTML / CSS 20

21 Individual level Typically stored as files on a workstation or small business server (.mdb,.accdb) Typically used by a few users at a time MS Access, Quicken/Quickbooks, Filemaker Company/Shared Stored on a database server and backed up regularly (hopefully ) Used by everyone in a company (thousands interact at any given time) Oracle, MySQL, Microsoft SQL Server E-Commerce Web-based databases Similar to company databases, but extra security is necessary MySQL, Oracle 21

22 Uses information in the database to help with business decision making Part of business information systems and informatics Examples Beer & Diapers at Walmart Target Databases (especially relational), are integral for this kind of work 22

23 A data warehouse is a database used for reporting and analysis The main source of the data is cleaned, transformed, catalogued and made available for use by managers and other business professionals for: data mining online analytical processing market research decision support 23

24 Is the analysis step of the knowledge discovery in databases process Is the process of discovering new patterns from large data sets involving methods at the intersection of artificial intelligence, machine learning, statistics and database systems The goal of data mining is to extract knowledge from a data set in a human-understandable structure Involves database and data management, data preprocessing, model and inference considerations, interestingness metrics, complexity considerations, postprocessing of found structure, visualization and online updating 24

25 The DBMS is one of the most critical systems in a corporate network The goal of HaX0rs Top priority is securing it Physical: Biometrics, alarms, etc. Network: Firewalls, antivirus, etc. 25

26 DB Admins Responsible for maintaining database functionality and securing it Also responsible for backups and presenting data to management Average salary is $87,000 ITP 320 ERP systems (large scale databases) ITP 300 Database web development 26