Бродяга wrote:Sabina, у Вас солидные знания в PL/SQL. Честно говоря у меня на работе нет ни одного программера, включая интерпрайз архитектора которые процедуры писать умеют:-)
даже глядя на пример ?
SBolgov wrote:Sabina wrote:Бродяга wrote:у меня на работе нет ни одного программера, включая интерпрайз архитектора которые процедуры писать умеют:-)
даже глядя на пример ?
А что это?
Sabina wrote:и правда все работает. спасибо за подсказку Vick_NJ не говорите
Бродяга wrote:Sabina, у Вас солидные знания в PL/SQL. Честно говоря у меня на работе нет ни одного программера, включая интерпрайз архитектора которые процедуры писать умеют:-)
AnyaGal wrote:определения степеней нормализации
Database Normalization
Normalization is a process of refining data model to ensure non-duplication of data and efficient organization of data is represented in the model.
1st Normal Form
This form of refinement assures that each table/relationship in a relational model contain scalar values only. In other words, each tuple contained in the entity has one and only value for each attribute defined in the table.
2nd Normal form
To be in 2nd normal form a relation must be in 1st normal form with the addition of every non-key attribute is dependent on only a portion of primary key. In other words no attribute is dependent only on a portion of primary key.
3rd normal form
It’s 2nr normal form plus all non-key attributes are transitively dependent on the primary key. In other words, No attribute will be dependent on any other attribute except primary key.
Boyce-Codd normal form
If you follow 1st, 2nd , 3rd normal forms, Boyce Codd is normally achieved automatically. However it is not always the case.
Boyce Codd is 3rd normal form + every determinant in a relationship is a candidate key. A Determinant is any attribute who’s value determines other value within a row.
So if relationship is in 3rd normal form and only has single possible key, then it’s also in Boyce Codd normal form