Chapter One: Introduction to Database Systems
0 likes7 views
this chapter deals with: Basic Concepts of Databases, Sources of data, Evolution of Database Database Benefits, Types of Database, Database Design, Characteristics of Database, and Jobs with Database.
Chapter One: Introduction to Database Systems
- 1. COURSE CODE : ECEg 4181 BY : EYOB S. EMAIL : eyobce@gmail.com 1
- 2. § Basic Concepts of Databases § Sources of data § Evolution of Database § Database Benefits § Types of Database § Database Design § Characteristics of Database § Jobs with Database 3/5/2024 ECEg 4181 - By: Eyob S. 2
- 3. § Data: raw facts § It must be formatted for processing and storage § Bigdata: refers to huge amount of data § Can be structured, unstructured or semistructured § Database: a collection of data organized to enable the creation, reading, updating, and deletion (CRUD) of data § Information: generated from processed data § It requires context to determine meaning § It can become knowledge used for decision making § Metadata: data about data, or description of the data 3/5/2024 ECEg 4181 - By: Eyob S. 3
- 4. § Data can be collected from different sources § You can collect from § Internet searching: e.g. Google Dataset, Kaggle, & Earthdata § Web scraping: is the process of using bots to extract content and data from a website. § Transactions: from finances, banks, etc. § Asking servers with APIs: e.g. about music in Spotify API § Querying a database,… etc. § Nowadays, any company uses data 3/5/2024 ECEg 4181 - By: Eyob S. 4
- 5. 3/5/2024 ECEg 4181 - By: Eyob S. 5
- 6. § Traditional § Manual System: Files, folders, file cabinets § Computerized: Apple numbers, Google sheet, MS excel – Poor structure: changing a structure breaks the system – Poor data dependency, redundancy, and inconsistency – Data insecurity, integrity issues, decentralized data, etc. § Hierarchical and Network Models were introduced in mid 1960s § In 1970s, Edgar F. Codd introduced the Relational Model, which provided a more flexible and intuitive way to organize and access data using tables and structural 3/5/2024 ECEg 4181 - By: Eyob S. 6
- 7. § Scale § Spreadsheets can hold thousands of records, whereas databases can hold millions or even billions of records § Frequency § Databases are designed to manage and process frequent data operations efficiently (realtime updates and queries) § Speed § Databases can perform queries, updates, and other transactions much faster 3/5/2024 ECEg 4181 - By: Eyob S. 7
- 8. § Centralized data § the data is centrally located and it is a collection of persistent data that can be shared and interrelated § Persistent – the data resides on stable storage since the data is repetitively used § Shared – the database can have multiple users § Interrelated – data stored as a separate unit can be connected to provide a whole picture § Database contains flood of data about many aspects which are useful for decision making 3/5/2024 ECEg 4181 - By: Eyob S. 8
- 9. 3/5/2024 ECEg 4181 - By: Eyob S. 9 § Single-user (PCs) or Multi-user (Workspaces, Enterprises) § Centralized or Distributed (multi-location) § Cloud database (MS Azure, Amazon AWS, IBM, Oracle, etc.) § General purpose / Discipline-specific § Operational (OLTP, Transactional, Production) or Analytical § Structured or Unstructured (or Semi-structured) § eXtensible Markup Language (XML) databases § Not only SQL (NoSQL)
- 10. § Logical data format § How you visualize your data § Draw the entity relationship diagram (ERD) § Physical data format § Actual database § Database management system (DBMS) § Database system environments § Hardware: electronic devices (server side, client side,…) § Software: OS (operating systems), DBMS, applications, etc. § Information: information lives in a database. § Procedure: how data get into a database or come out from it. § People: database expert, programmers, end user, etc. 3/5/2024 ECEg 4181 - By: Eyob S. 10
- 11. § DBMS (Database Management System) § A software though which you can interact with a database § DBMS is a software system that enables users to define, create, maintain, and control access to the database. § Examples: § MS Access § Oracle § MySQL 3/5/2024 ECEg 4181 - By: Eyob S. 11 § Ingres § MariaDB § PostgreSQL § Snowflake § SQLite,…etc. § MongoDB § DynamoDB § ScyllaDB § Redis § Neo4J § ArangoDB § Hbase § Cassandra,…etc.
- 12. § The most common query language is the Structured Query Language (SQL, pronounced “S-Q-L”, or sometimes “See- Quel”), which is now both the formal and de facto standard language for relational DBMSs. 3/5/2024 ECEg 4181 - By: Eyob S. 12
- 13. § JSON (JavaScript Object Notation) plays a crucial role in NoSQL databases, especially document-oriented databases like MongoDB, Couchbase, and Firebase. 3/5/2024 ECEg 4181 - By: Eyob S. 13
- 14. § Self-describing nature of the database system § Database contains not only the database itself but also metadata § Metadata is a complete definition(description) of the database structure and its constraints § Insulation between data and program § which is also called program data independence § Metadata is stored in the DBMS catalog separately from the access program § The characteristics that allow program data independence is called data abstraction 3/5/2024 ECEg 4181 - By: Eyob S. 14
- 15. § Support multiple user view of the data § A view may be a subset of the database, or it contain virtual data that is derived from the database files, but not explicitly stored § A database has different users and each of them may require a different perspective (view) of the database § Sharing of data and multiple user transaction processing § Concurrency control software to ensure that multiple users trying to update the same data, do so in a controlled manner, so that the result of the update must be correct § Isolation property ensures that each transaction appears to execute in isolation from other transactions, even though hundreds of transactions may be executing concurrently 3/5/2024 ECEg 4181 - By: Eyob S. 15
- 16. § DBMS has built-in facilities to support concurrent or parallel execution of database programs § Sequence of read/write operations considered to be an atomic unit in the sense that either all operations are executed or none at all § Read/write operations can be executed at the same time by the DBMS § DBMS should avoid any inconsistencies 3/5/2024 ECEg 4181 - By: Eyob S. 16
- 17. BACKUP AND RECOVERY FACILITIES § Backup and recovery facilities can be used to deal with the effect of loss of data due to hardware or network errors, or bugs in system or application software § Backup facilities can either perform a full or incremental backup § Recovery facilities allow restoration of the data to a previous state after loss or damage occurs 17
- 18. DATA SECURITY § Data security can be enforced by the DBMS § Some users have read access, while others have write access to the data (role-based functionality) § Sophisticated granularity is possible § Data access can be managed via logins and passwords assigned to users or user accounts § Each account has its own authorization rules that can be stored in the catalog 18
- 19. PERFORMANCE UTILITIES § There are three key performance indicators (KPIs) of a DBMS § Response time, denoting the time elapsed between issuing a database request and the successful termination thereof § Throughput rate, representing the transactions a DBMS can process per unit of time § Space utilization, referring to the space utilized by the DBMS to store both raw data and metadata § DBMSs come with various types of utilities aimed at improving these KPIs § e.g., utilities to distribute and optimize data storage, to tune indexes for faster query execution, to tune queries to improve application performance, or to optimize buffer management 19
- 20. § System administrator § Database designer § Database developer § Database manager § Data architect (e.g., in cloud computing) § Data security officer § Database consultant § Data modeler § Data analyst § Computer system analyst § Data security analyst § Data scientist § Computer scientist, etc. 3/5/2024 ECEg 4181 - By: Eyob S. 20