DBA KB: DBA & Data Topic

some tips for data migration, especially with bitfield, or "logical" field types.

by Jeffrey K. Tyzzer. In 1970, Dr. E.F. Codd's seminal paper "A Relational Model for Large Shared Databanks" was published in Communications of the ACM. This paper introduced the topic of data normalization, so-named because, at the time, President Nixon was normalizing relations with China.

Data normalization is a technique used during logical data modeling to ensure that there is only one way to know a fact, by removing all structures that provide more than one way to know the same fact as represented in a database relation (table). The goal of normalization is to control and eliminate redundancy, and mitigate the effects of modification anomalies -- which are generally insertion and deletion anomalies. (Insertion anomalies occur when the storage of information about one attribute requires additional information about a second attribute. Deletion anomalies occur when the deletion of one fact results in the loss of a second fact).

Normalization
There are six generally recognized normal forms of a relation: first normal form, second normal form, third normal form, Boyce/Codd normal form, fourth normal form, and fifth normal form, also called projection/join normal form. Other normal forms (e.g., Domain/Key) exist but will not be discussed here. The normal forms are hierarchical, i.e., each normal form builds upon its predecessor. Although many people consider a relation to be normalized only when it is in third normal form, technically speaking, a relation in only first normal form can be considered...

The following selects all the records in Table1 where IDField is not in Table2.

The ORA-00900 error displays automatically when erp is running properly but may be caused by a constraint violation.