slide môn học MySQL bài 1 database foundation knowledge

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Database Foundation knowledge Session Objectives(1)  Explain why we need a database  Explain the evolution of database management systems  Describe the basic concepts related to a database Concepts of RDBMS and SQL Server 2000/Session 1/ of 27 Objectives(2)   Explain the basic Relational database concepts • Entity integrity • Primary key • Foreign key • Relation and its degree related to a Describe a brief introduction of SQL Concepts of RDBMS and SQL Server 2000/Session 1/ of 27 What is a database? A database is an organized form of data consisting of one or more related data items called records A database is like a data collection to which we can ask different questions For example, “What are the phone numbers and addresses of the five nearest post offices?” Concepts of RDBMS and SQL Server 2000/Session 1/ of 27 Why use databases? Databases are used to store data in an efficient and organized manner A database allows us quick and easy management of data For example, a company may maintain details of its employees in a database FirstName LastName Hiredate Karla Jablonski 1994-03-11 Martine Rance 1992-02-05 Margaret Smith 1988-09-29 Gary Thomas 1988-08-09 Concepts of RDBMS and SQL Server 2000/Session 1/ of 27 Need for permanency Data storage can be achieved even using simple manual files However, data stored in this form is not permanent Concepts of RDBMS and SQL Server 2000/Session 1/ of 27 Problems with file storage The process of manually maintaining data through files is :    Tedious time consuming Error prone Concepts of RDBMS and SQL Server 2000/Session 1/ of 27 Evolution of DBMS-1 What is a DBMS? Database A003 Allen A007 Shane A004 Brian A008 Ricky Retrieve Data Insert Data Update Data DBMS Delete Data Concepts of RDBMS and SQL Server 2000/Session 1/ of 27 Basic Concepts of a database-1 Data Player Matches Won in the Series Information Lleyton Hewitt 20 Best Player of the Series Carlos Moya 15 Lleyton Hewitt Marat Safin 10 Paradorn Srichaphan Concepts of RDBMS and SQL Server 2000/Session 1/ of 27 Basic Concepts of a database-2 Tables are database objects that contain all the data present in a database Data in a table is arranged in rows Columns Rows and columns Concepts of RDBMS and SQL Server 2000/Session 1/ 10 of 27 Basic Concepts of a database-3  A database system is a computer-based record keeping system whose overall purpose is to record and maintain information  A DBMS is a collection of related records and a set of programs that access and manipulates these records Concepts of RDBMS and SQL Server 2000/Session 1/ 11 of 27 Basic Concepts of a database-4   Duplication of data or ‘data redundancy’ can be reduced using a database management system Ensuring the accuracy of data in the database is called maintaining the integrity of data Unique key RollNumber Name Sam John Jenny Lisa Wrong Concepts of RDBMS and SQL Server 2000/Session 1/ 12 of 27 Basic Concepts of a Relational database-1 Relational Database Applications for interacting with data in DB RDBMS A suite of S/W programs to create, maintain DB Concepts of RDBMS and SQL Server 2000/Session 1/ 13 of 27 Basic Concepts of a Relational database-2 Entities Tables Attributes Fields Relations Concepts of RDBMS and SQL Server 2000/Session 1/ 14 of 27 Basic concepts of Relational Database-3 A database is a collection of tables Each table contains information about a single entity A primary key is a column or combination of columns that uniquely identifies a record Primary Key Roll Number Student Name Sam John Jenny Lisa Penny Peter Joe Concepts of RDBMS and SQL Server 2000/Session 1/ 15 of 27 Entity Integrity   The Entity integrity rule states that no component of the primary key of a base table should be allowed to accept NULL values A NULL value is a missing value Roll Number Student Name Sam John Jenny Lisa Penny Peter Joe Invalid Concepts of RDBMS and SQL Server 2000/Session 1/ 16 of 27 Foreign key Two tables are linked together using a foreign key P F Roll Number Student Name Sam John Jenny John 65 Lisa Lisa 90 Penny Peter 87 Peter Joe 89 Joe Roll Number Student Name Marks Obtained Concepts of RDBMS and SQL Server 2000/Session 1/ 17 of 27 Referential Integrity The Referential integrity rule states that a database must not contain any unmatched foreign key values The DBMS is responsible for ensuring that the attribute values in the foreign key are valid and have a corresponding match in the relation where the attribute is a primary key Concepts of RDBMS and SQL Server 2000/Session 1/ 18 of 27 Relation and degree According to the relational model, every relation or table is made up of many tuples They are also called records For eg: CHN China Renminbi (Yuan) FRN France Francs The number of attributes within a table is called the degree of that table Concepts of RDBMS and SQL Server 2000/Session 1/ 19 of 27 [...]... data in the database is called maintaining the integrity of data Unique key RollNumber Name 1 Sam 2 John 3 Jenny 3 Lisa Wrong Concepts of RDBMS and SQL Server 2000/Session 1/ 12 of 27 Basic Concepts of a Relational database -1 Relational Database Applications for interacting with data in DB RDBMS A suite of S/W programs to create, maintain DB Concepts of RDBMS and SQL Server 2000/Session 1/ 13 of 27 Basic... a database- 3  A database system is a computer-based record keeping system whose overall purpose is to record and maintain information  A DBMS is a collection of related records and a set of programs that access and manipulates these records Concepts of RDBMS and SQL Server 2000/Session 1/ 11 of 27 Basic Concepts of a database- 4   Duplication of data or ‘data redundancy’ can be reduced using a database. .. Concepts of a Relational database- 2 Entities Tables Attributes Fields Relations Concepts of RDBMS and SQL Server 2000/Session 1/ 14 of 27 Basic concepts of Relational Database- 3 A database is a collection of tables Each table contains information about a single entity A primary key is a column or combination of columns that uniquely identifies a record Primary Key Roll Number Student Name 1 Sam 2 John 3 Jenny... Concepts of RDBMS and SQL Server 2000/Session 1/ 15 of 27 Entity Integrity   The Entity integrity rule states that no component of the primary key of a base table should be allowed to accept NULL values A NULL value is a missing value Roll Number Student Name 1 Sam 2 John 3 Jenny 4 Lisa 5 Penny Peter 7 Joe Invalid Concepts of RDBMS and SQL Server 2000/Session 1/ 16 of 27 Foreign key Two tables are linked... tables are linked together using a foreign key P F Roll Number Student Name 1 Sam 2 John 3 Jenny 2 John 65 4 Lisa 4 Lisa 90 5 Penny 6 Peter 87 6 Peter 7 Joe 89 7 Joe Roll Number Student Name Marks Obtained Concepts of RDBMS and SQL Server 2000/Session 1/ 17 of 27 Referential Integrity The Referential integrity rule states that a database must not contain any unmatched foreign key values The DBMS is responsible... Concepts of RDBMS and SQL Server 2000/Session 1/ 18 of 27 Relation and degree According to the relational model, every relation or table is made up of many tuples They are also called records For eg: CHN China Renminbi (Yuan) FRN France Francs The number of attributes within a table is called the degree of that table Concepts of RDBMS and SQL Server 2000/Session 1/ 19 of 27
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