tailieunhanh - Lecture Database design, application development and administration - Chapter 3: The relational data model

Chapter 3 - The relational data model. This chapter narrows your focus to the relational data model. Relational DBMSs dominate the market for business DBMSs. You will undoubtedly use relational DBMSs throughout your career as an information systems professional. This chapter provides background so that you may become proficient in designing databases and developing applications for relational databases in later chapters. | Chapter 3 The Relational Data Model Welcome to Chapter 3 covering the Relational Data Model Careful study of the relational data model Goal of chapter: Understand existing databases so that you can write queries Recognize relational database terminology Understand the meaning of the integrity rules for relational databases Understand the impact of referenced rows on maintaining relational databases Understand the meaning of each relational algebra operator List tables that must be combined to obtain desired results for simple retrieval requests Relational databases are the dominant commercial standard - Simplicity and familiarity with table manipulation - Strong mathematical framework - Lots of research and development Outline Relational model basics Integrity rules Rules about referenced rows Relational Algebra Relational model basics: - Tables - Columns and data types - Matching values - Alternative terminology - SQL CREATE TABLE statement Integrity rules: primary and foreign keys Referenced rows: actions when referenced rows are modified Relational algebra - Cover simple operators - Provide separate slide shows for join, outer join, and division operators - May want to mix relational algebra coverage with SQL Tables Relational database is a collection of tables Heading: table name and column names Body: rows, occurrences of data Student Partial Student table: - 5 columns - 3 rows - Real student table: 10 to 50 columns; thousands of rows Convention: - Table names begin with uppercase - Mixed case for column names - First part of column name is an abbreviation for the table name - Upper case for data CREATE TABLE Statement CREATE TABLE Student ( StdSSN CHAR(11), StdFirstName VARCHAR(50), StdLastName VARCHAR(50), StdCity VARCHAR(50), StdState CHAR(2), StdZip CHAR(10), StdMajor CHAR(6), StdClass CHAR(6), StdGPA DECIMAL(3,2) ) Define table name, column names, and column data types Other clauses added later in the lecture Data type: - Set of values - Permissible . | Chapter 3 The Relational Data Model Welcome to Chapter 3 covering the Relational Data Model Careful study of the relational data model Goal of chapter: Understand existing databases so that you can write queries Recognize relational database terminology Understand the meaning of the integrity rules for relational databases Understand the impact of referenced rows on maintaining relational databases Understand the meaning of each relational algebra operator List tables that must be combined to obtain desired results for simple retrieval requests Relational databases are the dominant commercial standard - Simplicity and familiarity with table manipulation - Strong mathematical framework - Lots of research and development Outline Relational model basics Integrity rules Rules about referenced rows Relational Algebra Relational model basics: - Tables - Columns and data types - Matching values - Alternative terminology - SQL CREATE TABLE statement Integrity rules: primary and foreign keys .

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