Week5September26摘要.pptVIP

Week 5September 26 Oracle: Control Files Basic Data Types SQL: Creating and Altering a Table,Imposing Integrity Constraints,DML SQL Terminology ISO terminology Relations (entity type) ? Tables Attributes (properties) ? Columns Tuples (entities) ? Rows Oracle Control Files Loads data into tables in batch mode Two parts Control language Data Anatomy of a Control FileUsing Displacement (i.e., Column Position) Anatomy of a Control FileUsing Displacement (i.e., Column Position) Anatomy of a Control FileUsing a Delimiter Basic Data Types in Oracle Anatomy of a CREATE TABLE Integrity Constraints Imposed to protect the database from becoming inconsistent Types: Required data Domain constraints Entity constraints Referential integrity Enterprise constraints Integrity Constraints Required data A column cannot be null (not null) Domain constraints Values assigned to a column must be from a defined domain Domain Constraint Using BETWEEN Integrity Constraints Entity constraints Primary key must contain a unique, no null value for each row Entity IntegrityComposite Key Integrity Constraints Referential integrity The value of a foreign key must exist in another table (i.e., parent) as at least a candidate key Normally, when a row in the parent is deleted and a child exists, one of fours actions can be taken: Cascade Set null* Set default* No action Integrity Constraints Integrity Constraints Enterprise constraints Organizational constraints (i.e., business rules) Another Example of Creating a Table with Referential Integrity Constraints Example of Creating a Table with Referential Integrity Constraints Example of Creating a Table with Referential Integrity Constraints In Case of Error…ALTER Table Alter table SQL command Add a column Modify a column Delete a column A column cannot be renamed Drop the column Add the column Adding a Column Modifying a Column Definition Deleting a Column Basic SQL: Data RetrievalFrom Relational Algebra to SQL Examples Using Products T