Assignment

Subjects:
- Math, Science, PE, Recees, Social Studies
Pitok
- Math,Science,PE,Recees
Kulas
- Math, Science, Social Studies
Jenny
- Science, Recess, Science
Aiza
- Science, Social Studies
JP Hentai
- Math
Selosya
- Recess
Honey
- Science, Math, Social Studies
Grace
- Recess

1. Display the name and subjects taken by all students
2. Display all students who are taking math subjects
3. Display the subjects of all HRM students

Database Joins

A foreign key is a column or group of columns in a relational database table that provides a link between data in two tables. It acts as a cross-reference between tables because it references the primary key of another table, thereby establishing a link between them.

SQL INNER JOIN Keyword

The INNER JOIN keyword selects records that have matching values in both tables.

INNER JOIN Syntax

SELECT column_name(s)
FROM table1
INNER JOIN table2ON table1.column_name = table2.column_name;

SQL LEFT JOIN Keyword

The LEFT JOIN keyword returns all records from the left table (table1), and the matched records from the right table (table2). The result is NULL from the right side, if there is no match.

LEFT JOIN Syntax

SELECT column_name(s)
FROM table1
LEFT JOIN table2ON table1.co

SQL RIGHT JOIN Keyword

The RIGHT JOIN keyword returns all records from the right table (table2), and the matched records from the left table (table1). The result is NULL from the left side, when there is no match.

RIGHT JOIN Syntax

SELECT column_name(s)
FROM table1
RIGHT JOIN table2ON table1.column_name = table2.column_name;lumn_name = table2.column_name;

SQL FULL OUTER JOIN Keyword

The FULL OUTER JOIN keyword returns all records when there is a match in left (table1) or right (table2) table records.

Note: FULL OUTER JOIN can potentially return very large result-sets!

Tip: FULL OUTER JOIN and FULL JOIN are the same.

FULL OUTER JOIN Syntax

SELECT column_name(s)
FROM table1
FULL OUTER JOIN table2ON table1.column_name = table2.column_nameWHERE condition;

What is Normalization?

Normalization is a database design technique which organizes tables in a manner that reduces redundancy and dependency of data.

It divides larger tables to smaller tables and links them using relationships.

https://www.guru99.com/database-normalization.html

SQL Database

The SQL CREATE DATABASE Statement

The CREATE DATABASE statement is used to create a new SQL database.

Syntax
CREATE DATABASE databasename;

The SQL DROP DATABASE Statement

The DROP DATABASE statement is used to drop an existing SQL database.

Syntax
DROP DATABASE databasename;

The SQL CREATE TABLE Statement

The CREATE TABLE statement is used to create a new table in a database.

Syntax
CREATE TABLE table_name (
    column1 datatype,
    column2 datatype,
    column3 datatype,
   ....
);
The column parameters specify the names of the columns of the table.

Example
CREATE TABLE Persons (
    PersonID int,
    LastName varchar(255),
    FirstName varchar(255),
    Address varchar(255),
    City varchar(255)
)

Create Table Using Another Table

A copy of an existing table can also be created using CREATE TABLE.

The new table gets the same column definitions. All columns or specific columns can be selected.

If you create a new table using an existing table, the new table will be filled with the existing values from the old table.

Syntax
CREATE TABLE new_table_name AS
    SELECT column1, column2,...
    FROM existing_table_name
    WHERE ....;

Example
CREATE TABLE TestTable AS
SELECT customername, contactname
FROM customers;

The SQL DROP TABLE Statement

The DROP TABLE statement is used to drop an existing table in a database.

Syntax
DROP TABLE table_name;

SQL ALTER TABLE Statement

The ALTER TABLE statement is used to add, delete, or modify columns in an existing table.

The ALTER TABLE statement is also used to add and drop various constraints on an existing table.

ALTER TABLE - ADD Column
To add a column in a table, use the following syntax:

ALTER TABLE table_name
ADD column_name datatype;

The following SQL adds an "Email" column to the "Customers" table:

Example
ALTER TABLE Customers
ADD Email varchar(255);

ALTER TABLE - DROP COLUMN
To delete a column in a table, use the following syntax (notice that some database systems don't allow deleting a column):

ALTER TABLE table_name
DROP COLUMN column_name;

The following SQL deletes the "Email" column from the "Customers" table:

Example
ALTER TABLE Customers
DROP COLUMN Email;
ALTER TABLE - ALTER/MODIFY COLUMN

To change the data type of a column in a table, use the following syntax:

ALTER TABLE table_name
MODIFY COLUMN column_name datatype;

SQL Create Constraints

Constraints can be specified when the table is created with the CREATE TABLE statement, or after the table is created with the ALTER TABLE statement.

Syntax
CREATE TABLE table_name (
    column1 datatype constraint,
    column2 datatype constraint,
    column3 datatype constraint,
    ....
);

SQL Constraints

SQL constraints are used to specify rules for the data in a table.

Constraints are used to limit the type of data that can go into a table. This ensures the accuracy and reliability of the data in the table. If there is any violation between the constraint and the data action, the action is aborted.

Constraints can be column level or table level. Column level constraints apply to a column, and table level constraints apply to the whole table.

The following constraints are commonly used in SQL:

NOT NULL - Ensures that a column cannot have a NULL value
UNIQUE - Ensures that all values in a column are different
PRIMARY KEY - A combination of a NOT NULL and UNIQUE. Uniquely identifies each row in a table
FOREIGN KEY - Uniquely identifies a row/record in another table
CHECK - Ensures that all values in a column satisfies a specific condition
DEFAULT - Sets a default value for a column when no value is specified

SQL NOT NULL Constraint

By default, a column can hold NULL values.

The NOT NULL constraint enforces a column to NOT accept NULL values.

This enforces a field to always contain a value, which means that you cannot insert a new record, or update a record without adding a value to this field.

SQL NOT NULL on CREATE TABLE
The following SQL ensures that the "ID", "LastName", and "FirstName" columns will NOT accept NULL values when the "Persons" table is created:

Example
CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255) NOT NULL,
    Age int
);

SQL UNIQUE Constraint

The UNIQUE constraint ensures that all values in a column are different.

Both the UNIQUE and PRIMARY KEY constraints provide a guarantee for uniqueness for a column or set of columns.

A PRIMARY KEY constraint automatically has a UNIQUE constraint.

However, you can have many UNIQUE constraints per table, but only one PRIMARY KEY constraint per table.

SQL UNIQUE Constraint on CREATE TABLE
The following SQL creates a UNIQUE constraint on the "ID" column when the "Persons" table is created:

SQL Server / Oracle / MS Access:

CREATE TABLE Persons (
    ID int NOT NULL UNIQUE,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int
);

MySQL:

CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int,
    UNIQUE (ID)
);

SQL UNIQUE Constraint on ALTER TABLE
To create a UNIQUE constraint on the "ID" column when the table is already created, use the following SQL:

MySQL / SQL Server / Oracle / MS Access:

ALTER TABLE Persons
ADD UNIQUE (ID);

DROP a UNIQUE Constraint
To drop a UNIQUE constraint, use the following SQL:

MySQL:

ALTER TABLE Persons
DROP INDEX UC_Person;

SQL Server / Oracle / MS Access:

ALTER TABLE Persons
DROP CONSTRAINT UC_Person;

SQL PRIMARY KEY Constraint

The PRIMARY KEY constraint uniquely identifies each record in a table.

Primary keys must contain UNIQUE values, and cannot contain NULL values.

A table can have only ONE primary key; and in the table, this primary key can consist of single or multiple columns (fields).

SQL PRIMARY KEY on CREATE TABLE
The following SQL creates a PRIMARY KEY on the "ID" column when the "Persons" table is created:

MySQL:

CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int,
    PRIMARY KEY (ID)
);

SQL Server / Oracle / MS Access:

CREATE TABLE Persons (
    ID int NOT NULL PRIMARY KEY,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int
);

SQL PRIMARY KEY on ALTER TABLE
To create a PRIMARY KEY constraint on the "ID" column when the table is already created, use the following SQL:

MySQL / SQL Server / Oracle / MS Access:

ALTER TABLE Persons
ADD PRIMARY KEY (ID);

SQL CHECK Constraint

The CHECK constraint is used to limit the value range that can be placed in a column.

If you define a CHECK constraint on a single column it allows only certain values for this column.

If you define a CHECK constraint on a table it can limit the values in certain columns based on values in other columns in the row.

SQL CHECK on CREATE TABLE
The following SQL creates a CHECK constraint on the "Age" column when the "Persons" table is created. The CHECK constraint ensures that you can not have any person below 18 years:

MySQL:

CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int,
    CHECK (Age>=18)
);

SQL Server / Oracle / MS Access:

CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int CHECK (Age>=18)
);

SQL CHECK on ALTER TABLE
To create a CHECK constraint on the "Age" column when the table is already created, use the following SQL:

MySQL / SQL Server / Oracle / MS Access:

ALTER TABLE Persons
ADD CHECK (Age>=18);

SQL DEFAULT Constraint

The DEFAULT constraint is used to provide a default value for a column.

The default value will be added to all new records IF no other value is specified.

SQL DEFAULT on CREATE TABLE
The following SQL sets a DEFAULT value for the "City" column when the "Persons" table is created:

My SQL / SQL Server / Oracle / MS Access:

CREATE TABLE Persons (
    ID int NOT NULL,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int,
    City varchar(255) DEFAULT 'Sandnes'
);

The DEFAULT constraint can also be used to insert system values, by using functions like GETDATE():

CREATE TABLE Orders (
    ID int NOT NULL,
    OrderNumber int NOT NULL,
    OrderDate date DEFAULT GETDATE()
);

SQL DEFAULT on ALTER TABLE
To create a DEFAULT constraint on the "City" column when the table is already created, use the following SQL:

MySQL:

ALTER TABLE Persons
ALTER City SET DEFAULT 'Sandnes';

DROP a DEFAULT Constraint
To drop a DEFAULT constraint, use the following SQL:

MySQL:

ALTER TABLE Persons
ALTER City DROP DEFAULT;

SQL Server / Oracle / MS Access:

ALTER TABLE Persons
ALTER COLUMN City DROP DEFAULT;

AUTO INCREMENT Field

Auto-increment allows a unique number to be generated automatically when a new record is inserted into a table.

Often this is the primary key field that we would like to be created automatically every time a new record is inserted.

Syntax for MySQL
The following SQL statement defines the "Personid" column to be an auto-increment primary key field in the "Persons" table:

CREATE TABLE Persons (
    Personid int NOT NULL AUTO_INCREMENT,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int,
    PRIMARY KEY (Personid)
);

Syntax for SQL Server
The following SQL statement defines the "Personid" column to be an auto-increment primary key field in the "Persons" table:

CREATE TABLE Persons (
    Personid int IDENTITY(1,1) PRIMARY KEY,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int
);

Structured Query Language (SQL)

Click here to Download Sample Data

What is SQL?

• SQL stands for Structured Query Language
• SQL lets you access and manipulate databases
• SQL became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standardization (ISO) in 1987

The SQL SELECT Statement

The SELECT statement is used to select data from a database.
The data returned is stored in a result table, called the result-set.

SELECT Syntax
SELECT column1, column2, ...
FROM table_name;

The SQL SELECT DISTINCT Statement

The SELECT DISTINCT statement is used to return only distinct (different) values.

Inside a table, a column often contains many duplicate values; and sometimes you only want to list the different (distinct) values.

SELECT DISTINCT Syntax
SELECT DISTINCT column1, column2, ...
FROM table_name;

The SQL WHERE Clause

The WHERE clause is used to filter records.

The WHERE clause is used to extract only those records that fulfill a specified condition.

WHERE Syntax
SELECT column1, column2, ...
FROM table_name
WHERE condition;

The SQL AND, OR and NOT Operators

The WHERE clause can be combined with AND, OR, and NOT operators.

The AND and OR operators are used to filter records based on more than one condition:

• The AND operator displays a record if all the conditions separated by AND are TRUE.
• The OR operator displays a record if any of the conditions separated by OR is TRUE.
• The NOT operator displays a record if the condition(s) is NOT TRUE.

AND Syntax

SELECT column1, column2, ...
FROM table_name
WHERE condition1 AND condition2 AND condition3 ...

OR Syntax

SELECT column1, column2, ...

FROM table_name

WHERE condition1 OR condition2 OR condition3 ...

NOT Syntax

SELECT column1, column2, ...

FROM table_name

WHERE NOT condition

NULL Values

It is not possible to test for NULL values with comparison operators, such as =, <, or <>.

We will have to use the IS NULL and IS NOT NULL operators instead.

IS NULL Syntax

SELECT column_names

FROM table_name

WHERE column_name IS NULL

IS NOT NULL Syntax

SELECT column_names

FROM table_name

WHERE column_name IS NOT NULL

The SQL SELECT TOP Clause

The SELECT TOP clause is used to specify the number of records to return.

The SELECT TOP clause is useful on large tables with thousands of records. Returning a large number of records can impact performance.

Note: Not all database systems support the SELECT TOP clause. MySQL supports the LIMIT clause to select a limited number of records, while Oracle uses ROWNUM.

SQL Server / MS Access Syntax:

SELECT TOP number|percent column_name(s)

FROM table_name

WHERE condition;

MySQL Syntax:

SELECT column_name(s)

FROM table_name

WHERE condition

LIMIT number;

Oracle Syntax:

SELECT column_name(s)

FROM table_name

WHERE ROWNUM <= number;

The SQL MIN() and MAX() Functions

The MIN() function returns the smallest value of the selected column.

The MAX() function returns the largest value of the selected column.

MIN() Syntax

SELECT MIN(column_name)

FROM table_name

WHERE condition

MAX() Syntax

SELECT MAX(column_name)

FROM table_name

WHERE condition

The SQL COUNT(), AVG() and SUM() Functions

The COUNT() function returns the number of rows that matches a specified criteria.

The AVG() function returns the average value of a numeric column.

The SUM() function returns the total sum of a numeric column.

COUNT() Syntax

SELECT COUNT(column_name)

FROM table_name

WHERE condition;

AVG() Syntax

SELECT AVG(column_name)

FROM table_name

WHERE condition;

SUM() Syntax

SELECT SUM(column_name)

FROM table_name

WHERE condition;

The SQL LIKE Operator

The LIKE operator is used in a WHERE clause to search for a specified pattern in a column.

There are two wildcards often used in conjunction with the LIKE operator:

% - The percent sign represents zero, one, or multiple characters

_ - The underscore represents a single character

Note: MS Access uses an asterisk (*) instead of the percent sign (%), and a question mark (?) instead of the underscore (_).

The percent sign and the underscore can also be used in combinations!

LIKE Syntax

SELECT column1, column2, ...

FROM table_name

WHERE columnN LIKE pattern

The SQL IN Operator

The IN operator allows you to specify multiple values in a WHERE clause.

The IN operator is a shorthand for multiple OR conditions.

IN Syntax

SELECT column_name(s)

FROM table_name

WHERE column_name IN (value1, value2, ...);

or:

SELECT column_name(s)

FROM table_name

WHERE column_name IN (SELECT STATEMENT);

The SQL BETWEEN Operator

The BETWEEN operator selects values within a given range. The values can be numbers, text, or dates.

The BETWEEN operator is inclusive: begin and end values are included. 

BETWEEN Syntax

SELECT column_name(s)

FROM table_name

WHERE column_name BETWEEN value1 AND value2

SQL Aliases

SQL aliases are used to give a table, or a column in a table, a temporary name.

Aliases are often used to make column names more readable.

An alias only exists for the duration of the query.

Alias Column Syntax

SELECT column_name AS alias_name

FROM table_name;

Alias Table Syntax

SELECT column_name(s)

FROM table_name AS alias_name;

The SQL GROUP BY Statement

The GROUP BY statement groups rows that have the same values into summary rows, like "find the number of customers in each country".

The GROUP BY statement is often used with aggregate functions (COUNT, MAX, MIN, SUM, AVG) to group the result-set by one or more columns.

GROUP BY Syntax
SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
ORDER BY column_name(s);

Example
SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country;

The SQL HAVING Clause

The HAVING clause was added to SQL because the WHERE keyword could not be used with aggregate functions.

HAVING Syntax
SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
HAVING condition
ORDER BY column_name(s);

Example
SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country

HAVING COUNT(CustomerID) > 5;

Sample Data

Download Sample Data

The Systems Analyst

A Systems Analyst is a person who uses analysis and design techniques to solve business problems using informatino techology. Systems Analyst may serve as change agents who identify the organizational improvements needed, design systems to implement these changes and train and motivate others to use the system.

Roles of a Systems Analyst

Act as a middleman and an architect.
System analysts liaise between customers, IT persons, and stakeholders to develop information systems capable of delivering business requirements. The integration of technology into business requirements has to be futuristic. It means systems analysts have to develop information systems that are easy to upgrade in the future if the need arises. They have to design an information system architecture according to the user’s requirements which acts as a blueprint for the programmers. For that, they need to know exactly what users want and also have to build good relationships and rapport with them to understand their requirements as well as convey correct and complete information to the development team.

Agent of Change
System analysts are also known as an agent of change since they use different approaches to bring changes in the information system that can facilitate business operations. The biggest hurdle for the role of system analysts is the skepticism of people about accepting the change. So, they prefer users' participation for easy exchange of information. When stakeholders, management, and clients are ready for the technological changes, a final system is made.

Investigator and Monitor
In defining a problem or finding reasons for the failure in a system, system analysts play a role of an investigator. They gather information to determine or investigate why an existing system is not working well and is facing problems and what changes should be implemented to solve these issues. After creating alternative solutions for problems, system analysts monitor the information system regularly and take steps to avoid increased costs, and the waste of resources and time.

Motivator and Sales Person
Effective user participation and training with proper motivation to use the system are important factors to achieve system acceptance. Another important role that system analysts play is of a salesperson, which involves selling a system to the users. This process takes place at each stage of system life cycle. To play the role of a motivator and sales person, system analysts have to hold good communication, sales, and persuasion skills.

Responsibilities of System Analysts:

Defining User Requirements
The basic and most important step for system analysts is to understand user’s requirements clearly. To get the hang, they have to interview users and prepare questionnaires, observe the current system, and plan system configuration. This phase is important to understand how the current system functions and what users want from the new systems. Participation of users is needed so that their views related to the system are taken into consideration to build the new one.

Prioritizing Requirements
Large systems do have various requirements which are not equal and are, therefore, not possible for the team to implement all of them at the same time. Also, various types of users in the organization have different types of information needs that cannot be satisfied due to various constraints such as limited resources, budgetary constraints, time sensitivity, feasibility, etc. Therefore, system analysts have to prioritize users’ requirements using their social and analytical skills.

Gathering Data and Facts
System analysts act as researchers and gather various facts and data with the active cooperation from the users of the system. They consult users from time to time to obtain necessary information related to the system, and whether there is any last-minute requirement. This process is important because analysts have to organize and document information into functional specification to solve to develop a system.

Analyzing the Problem
After gathering data and facts, system analysts analyze various problems, their causes, and effects on business operations. They analyze and identify the requirements to be fulfilled through technological means. They remove unnecessary data, focus on the important ones, and change or modify the working system accordingly to make it more user-friendly.

Solving Problems
System analysts help IT users to solve information problems by using different approaches in which one good source of solutions is to take suggestions from others. With this approach, analysts develop and evaluate a set of possible alternative solutions and then compare and choose the best one to implement. They have to compare the alternative solutions on the basis of cost, benefits, risk factors, etc. and decide the best with management's help.

Drawing Specifications
System analysts are responsible for drawing precise and clear specifications for programmers and managers to understand easily. That includes text, documents, and flow charts for visual understanding of computer programmers. These are presented in a detailed form as they lay the foundations for optimal functioning of the system.

Designing and Evaluating Systems
At last, when the analysts are done with the preparation of the system's specifications, they design and implement the system along with the development team so that the management’s goal is achieved. With the knowledge of advanced programming tools, they act as an architect and develop new systems. After the system is developed, they test the performance and recommend necessary modifications.

Due to the various roles and responsibilities of a system analyst, he/she has to be a multifaceted personality who is able to manage and coordinate with various people.

Skills of a Systems Analyst

Interpersonal skills
- Communication - is not just reports, telephone conversations and interviews or one's command of the English language. It is also people talking, listening, feeling and reacting to one another, their experiences and reactions
- Understanding - identifying problems and assessing their ramifications, having a grasp of company goals and objectives and showing sensitivity to the impact of the system on people at work
- Teaching - educating people in use of computer systems. He has to teach about the new system and also about the proper use of the new system.
- Selling - selling ideas and promoting innovations in problem solving using computers. The system analyst must have not only the ability of creating ideas but also to sell his ideas.

Technical Skills

Performance Tuning
Computers, routers, programs and networks are configured to provide the best working conditions for employees. Analysts need to understand how everything at the site works together and be able to fine-tune and enhance areas that require attention. Monitoring bottlenecks that slow down company productivity and then adjusting system programs to alleviate the problems are all in a day's work.

Programming Languages
Knowledge and familiarity with common programming languages  are useful in the workplace. Systems analysts don’t necessarily need to do the coding, but they should be able to read it. That way they can discuss it with the programmers who are responsible for modifying it.

Computer Platforms
Familiarity with operating systems such as AIX, Windows, Mac and Linux is useful in environments that use many technologies or if a job requires lots of travel.

Hardware Capabilities
In-depth knowledge of the types of hardware in use at each job site is necessary for the systems analyst to ascertain the extent of computer problems and possible equipment damage. Knowledge of the storage and computing capacity of computers, routing equipment, printers and external and Bluetooth devices can help employees continue to work while repairs are made.

Network Structure and Function
Analysts deal with computers on networks, so it is only logical that they are familiar with network topologies, or structures, and also how to administer a network. Skills of this sort are generally gained on the job and also through classes taught by companies that produce networking software.

Data Structures
Data is everywhere in the workplace, and databases are common at all companies, big and small. Proprietary company databases and more common ones such as Oracle and Foxpro used across industry are based on similar data structures.

Computer Security
Security breaches are more common than ever, and analysts help keep computers free of viruses and other invasive nuisances. They help develop strategies to ensure on-site data integrity. Analysts help define company policies regarding computer security such as not allowing employees to download software onto networks.

Information Systems

Introduction
 - copmanies use information as a weapon in the battle to increase productivity, deliver quality products and services, maintain customer loyalty and make sound decisions 
 - Information technology can mean the difference between success and failure

Information Technology
 - combination of hardware products and services that companies use to manage, access, communicate and share information

Systems Analysis and Design
 - step by step process fo developing high quality information systems
What Does a Systems Analyst Do?
 - plan, develop and maintain information systems
 - also manages IT projects, including tasks, resources, schedules and documentation

Information System Components
 - a system is a set or related components that produces specific results
 - 5 components are 
 Hardware -  the physical layer of the information system

 Software - the programs that are needed to accomplish the input, processing, output, storage, and control activities of information systems. Computer software is typically classified into two major types of programs: a) system software - Systems software are programs that manage the resources of the computer system and simplify applications programming.
b) application software - are programs that direct the performance of a particular use, or application, of computers to meet the information processing needs of end user

 Data - information that has been translated into a form that is efficient for movement or processing. Raw data is a term used to describe data in its most basic digital format.

 Processes - a series of tasks that are completed in order to accomplish a goal. A business process, therefore, is a process that is focused on achieving a goal for a business. 

 People - people who are involved in the information system
  - Systems Analyst - The role of the systems analyst is to straddle the divide between identifying business needs and imagining a new or redesigned computer-based system to fulfill those needs
  - Programmer - generally attempt to fulfill the design specifications given to them by a systems analyst
  Computer Engineer - design the computing devices that we use every day
  Computer Operator - is the person who keeps the large computers running
  Database Administrators - is the person who manages the databases for an organization. This person creates and maintains databases that are used as part of applications or the data warehouse. The DBA also consults with systems analysts and programmers on projects that require access to or the creation of databases.
  Trainer, Help Desk, etc.

Business Trends in the 21st Century
 - Rapidly inceasing globalization
 - Technology integration for seamless information access
 - Rapid growth of cloud-based computing and services
 

Database 01

Why Study Databases
- many computing applications deal with large amounts of information
- Database systems give a set of tools for stoingm searching and managing this information

What is a Database
-  a set of informatino held in a computer
- one or more large structured sets of persistent data, usually associated with software to update and query the data
- a collection of data arranged for ease and speed of search and retrieval

Examples of Databases
- web indexes - library catalogues
- Medical records - airline bookings
- Bank accounts - Student records
- Stock control - customer histories
- Product Catalogues - Contact list
- etc....

Database Systems
 -a database system is consist of:
- Data
- Software
- Hardware
- Users
 - database systems allow users to
- store
- update
- retrieve
- organize
- protect
  their data

Database Users
- End Users - use the database system to achieve some goals
- Application Developers - write software to allow end users to interface with the database system
- Database Administrators - designs and manages the database system
- Database systems programmer - writes the database software itself

Database Management Systems
- a database os a collection of information
- a database management system (DBMS) is the software that controls that information
- examples :
- Oracle - MySQL
- SQLite - MS SQL Server
- PpostgreSQL - DB2 (IBM)

What the DBMS Does
- provides users with
- Data Definition Language (DDL)
- Data Manipulatin Language (DML)
- Data Control Language (DCL)
- DBMS provides
- Persistence
- Concurrency
- Integrity
- Security
- Data Independence

File Based Systems
- Data is stored in files
- Each file has a specific format
-Programs that use these files depend on knowledge about that format

Problems :
- No standards
- Data duplication
- Data dependence
- No way to generate ad hoc queries
- No provision for security, recovery,  concurrency, etc.