Data and Information: Database Systems

Data and Information

• Data includes dates, values, and names.
  • For example: "21/04/1998", "Frank", "Luton", "Derby".
• Information is data given context, providing it with meaning.
• Information describes relationships between different pieces of data.
  • For example: "Frank Derby was born in Luton on 21/04/1998".

Evolution of Database Systems

• Databases consist of information collected over time.
• Data and information are valuable assets for businesses.
• Data consists of raw facts, events, and transactions managed by a Database Management System (DBMS) in a business setting.
• Information is data that has been processed for use.
• Ted Codd developed the database for IBM in the 1970s.
• Codd won the Turing Award in 1981.

Information Process

• Information processing involves data capture, recording, and storage,
• Data processing consists of updating, deleting, and retrieval
• Data output and presentation.

Database Management System (DBMS) Expectations

• Enable database structure creation.
• Allow users to query data using appropriate languages.
• Support storage of large data amounts over long periods.
• Provide recovery from failures, errors, or misuse.
• Manage data access for multiple users with security measures.

Evolution and Terminologies Associated with Systems

• Manual and Computerised Systems use files, records, data items/fields, and cabinets.
• Database Systems use relations/tables, rows/tuples, columns/attributes, objects/entities, and relationships.
• UML Systems use classes/sub Classes, associations, attributes, methods, operations, and inheritance.

Systems Essential to Every Business

• Manual and Computerised Files considerations include their appearance, functionality, and limitations
• Database Systems are used daily and come with their own appearance, associated concepts, and functionality.

Example: Customer Table (or Relation)

• The customer table shows the "Cust_ID", "F_Name", "L_Name", and "DOB" attributes
• A record (or tuple) shows the information for one customer

Increase in Size Requirements

• DBMS in the 1970s were used for banking, airline reservation systems, and corporate record keeping.
• More recently, Google stores exabytes of web data using specialized structures for search engine queries.
• Satellites store petabytes of information in specialized systems.
• Pictures take up more storage space than words
• Videos use gigabytes of space, like on YouTube.
• 1 Exabyte equates to 1,000,000,000 GB.

Data Size

• Bit (b) is 0 or 1
• Byte (B) is 8 bits
• Kilobyte (KB) is 1000¹ bytes in decimal value and 1024¹ bytes in binary value
• Megabyte (MB) is 1000² bytes in decimal value and 1024² bytes in binary value
• Gigabyte (GB) is 1000³ bytes in decimal value and 1024³ bytes in binary value
• Terabyte (TB) is 1000⁴ bytes in decimal value and 1024⁴ bytes in binary value
• Petabyte (PB) is 1000⁵ bytes in decimal value and 1024⁵ bytes in binary value
• Exabyte (EB) is 1000⁶ bytes in decimal value and 1024⁶ bytes in binary value
• Zettabyte (ZB) is 1000⁷ bytes in decimal value and 1024⁷ bytes in binary value
• Yottabyte (YB) is 1000⁸ bytes in decimal value and 1024⁸ bytes in binary value
• A Nibble is 4 bits (not shown)

What Databases Look Like

• A database is a collection of related data, and DBMS is software that manages and controls access.
  • Example DBMS programs: MS Access, Oracle SQL, MySQL, SQl Server, Foxpro, SQL Lite, MongoDBetc.

Database Management System Components

• Key components include user apps, query compiler, transaction manager, DDL compiler, execution engine, logging recovery, concurrency control, index/file/record, buffer manager, buffers, lock table, storage manager, and storage along with DB Admin duties

Pros and Cons of Database Systems

• Advantages include control of data redundancy, data consistency, more information from the same amount of data, data sharing, improved security, enforcement of standards, improved maintenance through data independence, and increased concurrency.
• Disadvantages include complexity, size, cost of DBMSs, additional hardware costs, cost of conversion, performance issues, and a higher impact of failure.

Database Design Steps

• Determine the database's purpose & its information requirements
• Analyse the system,
• Produce a Conceptual Entity Relationship Model,
• Normalise the database design.
• Convert the conceptual data model to a physical data model.

Database System Studies

• Areas of study include relational database modeling, relational database programming.
• Areas of study include web development and database systems implementation.
• Areas of study include modern database systems and search engines.

Summary

• Data is a valuable corporate asset.
• Data processing helps in making informed decisions
• Information processing involves distinct phases.
• You must be aware of manual file systems, computerised file systems and database systems
• Understanding database concepts and terminologies like data, information, record, field, file, and DBMS is important.