Introduction

GENERAL:

• SQL is 4GL.
• “” can be used to make case sensitive for column names.
• Schema is like a folder in a database. It is objects that can be owned by a user account.

NORMAL FORM:

• 1NF –> No repeating groups 2-dimensional.
• 2NF –> Primary key that is not composite.
• 3NF –> No data that does not provide the intend of primary key.
• Boyce-Codd NF –> Remove certain rare logical inconsistencies.
• 4NF –> Every multivalued dependency is dependent on a super key.
• 5NF –> Every join dependency is a result of the candidate keys.

NAMESPACE:

• USER, ROLES, PUBLIC SYNONYMNS System.
• TABLE, VIEW, SEQUENCE, PRIVATE SYNONYMNS, USER DEFINED TYPES Schema.
• INDEX Schema.
• CONSTRAINT Schema.

DATATYPES:

• CHAR(n) Retrieved with spaces.
• VARCHAR2(n).
• NUMBER(n, m) n is precision – total number in either side after scaling m is scale – total number on right side of decimal point. If a value has more significant digits to the left of the decimal place than are specified in the format, then pound signs (#) replace the value. If a positive value is extremely large and cannot be represented in the specified format, then the infinity sign (~) replaces the value. Likewise, if a negative value is extremely small and cannot be represented by the specified format, then the negative infinity sign replaces the value (-~).
• DATE NLS_DATE_FORMAT NLS_TERRITORY.
• TIMESTAMP(n 1-9/6).
• TIMESTAMP(n 1-9/6) WITH TIMEZONE.
• TIMESTAMP(n 1-9/6) WITH LOCAL TIMEZONE.
• INTERVAL YEAR(n 1-9/2) TO MONTH.
• INTERVAL DAY(n1 1-9/2) TO SECOND(n2 1-9/6).
• BLOB.
• CLOB.
• NCLOB (UTF).