Minimum no of tables that exists after decomposing relation R into 1NF?

If all the candidate keys of a relation contain multivalued attributes: Introduce a surrogate attribute for at least one multivalued attribute. For each attribute you deem “composite” (having heterogeneous components, like a tuple): For each attribute component that can be missing: Add a relation with attributes of some multivalue-free candidate key and an attribute for … Read more

have address columns in each table or an address table that is referenced by the other tables?

Database Normalization is all about constructing relations (tables) that maintain certain functional dependencies among the facts (columns) within the relation (table) and among the various relations (tables) making up the schema (database). Bit of a mouth-full, but that is what it is all about. A Simple Guide to Five Normal Forms in Relational Database Theory … Read more

Convert String ISO-8601 date to oracle’s timestamp datatype

The date format model elements are listed in the Datetime Format Models documentation: SELECT to_timestamp_tz (‘2014-09-12T11:53:06+00:00’, ‘YYYY-MM-DD”T”HH24:MI:SSTZH:TZM’) FROM DUAL TO_TIMESTAMP_TZ(‘2014-09-12T11:53:06+00:00′,’YYYY-MM-DD”T”HH24:MI:SSTZH:TZM’) ————————————————————————— 12-SEP-14 +00:00 The fixed T can be included as a character literal: You can include these characters in a date format model: Punctuation such as hyphens, slashes, commas, periods, and colons Character literals, … Read more

Alternatives to Entity-Attribute-Value (EAV)?

There is a difference between EAV done faithfully or badly; 5NF done by skilled people or by those who are clueless. Sixth Normal Form is the Irreducible Normal Form (no further Normalisation is possible). It eliminates many of the problems that are common, such as The Null Problem, and provides the ultimate method identifying missing … Read more