Interview about Oracle

Oracle Lawrence Ellison Larry Ellison

History

1. Human Management Phase
2. Document Management Phase
3. Database System phase

Model: "Models are a form of expression of a system, process, thing, or concept being studied"

1. Hierarchy model
2. Mesh Structure Model
3. Relational Structure model

Schema: "Abstract of the real world, logical structure and characteristic for db all data"

1. Mode logical
2. External mode manipulation
3. Internal Mode physical

Image

1. External mode/mode logical Independence
2. Mode/internal mode physical independence

Term

1. Table: The data table used in the DB.
2. Virtual tables in view view:db, "storing records from query in DB table records"
3. Stored procedure: A block of statements consisting of SQL statements and control-flow statements.
4. Triggers: Special stored procedures, which are executed automatically in the DB without requiring a call.
5. Constraint: the means by which data integrity in the table in DB is guaranteed in db.

• • PRIMARY KEY PRIMARY KEY constraint
  • FOREIGN key FOREIGN KEY constraint
  • Uniquely UNIQUE constraint
  • Checking CHECK constraints
  • Non-empty NOT NULL constraint

Completeness: DB design integrity is actually correctness to ensure data correctness.

1. Entity integrity
2. Zone integrity
3. Referential integrity

Paradigm: The design standard for relationship db is the paradigm of DB.

1. First Paradigm
2. Second Paradigm
3. Third Paradigm

Oracle stored procedure: is a PL/SQL block of code that is stored in DB server that encapsulates one or more segments

Role:

1. Simplify complex operations　
2. Increase data independence
3. Improve security
4. Improve performance