It is too fussy to put forward extract field from
many tables one by one, therefore it needs to be
dealt with it in a structural processing, when
unstructural fields switch into structural fields, we
need to deal with the following conflicts:
(1) Naming conflicts
Description: if two elements E1 and E2 express
the same entity, but different names, it is happened
the conflicts of naming synonym. When the
elements E1 and E2 have different names but means
different entity or concept, it will occur the conflict
of homonymy. For example, using permanent
population at the end of years in the table T1 means
the number of permanent population; at the table T2,
using the total population expresses the number of
permanent population, then it will occurs the conflict
of class name synonymous between long-term
populations at the end of the years. Absolute
(number /all workers) means the absolute number
of the workers' salary in the table A1; Absolute
(number/ all workers) means the absolute average
wages in the table A2. The conflict of class name
homonymy word is happened.
The forms of relational model conflicts: Using
class in the relation bag represents entity or concept,
so the name conflicts in the model performance class
names with the same form and synonymous
conflicts.
Solving strategy: the Abnormity synonyms
conflicts tip the synonyms checked by HUB
according to input the synonyms by users;
Homonymy conflicts find the conflict according to
matching class-name users choose the method to
solve the conflicts
(2) Date type conflicts
Description; suppose that A1 and A2 describe
the character of the same entity but have different
date model A1 and A2 have date model conflicts.
For example, the date model of agricultural output is
plastic in the table 1. The date model of agricultural
output is character type in the table2.
The form of the conflicts of relation model;
relevance of column and date type expresses the date
type of a field. So the conflict is happen, when data
type of relevant field is different.
Solving strategy: Matching means the same
character of column, which is relevant for the date
type, users can choose date type.
(3) The conflict of Data dimension
Description: Suppose A1and A2 describe the
same features of the same entity, but date dimension
is different between A1and A2, they exist the
conflict of date dimension. Such as using meter
expresses height in the table 1; using inch expresses
height in table 2.It cannot know the date dimension
in the date dictionary. That is to say, database
metadata does not provide dimension of semantics.
The form of conflict model; there is no the
express way of the date dimension, when model
integration, it does not check the date dimension.
Suppose that users understand the conflicts of the
date dimension in the two tables, user solve it by
herself.
(4) Numerical range and Precision conflict
Description: related objects equivalent data
elements have different range and accuracy settings.
For instance, in the table T1, Agricultural
output value of the unit price is six-figure, the two-
figure behind point, such as 1000.82;in the table
2,the unit price of the total agriculture production is
five- figure, the behind of the point is one- figure,
such as 1200.5.
The form of the relation model conflict;
attribute setting in the relation bag express the scope
and precision which is list in the date base, the
conflicts of scope and precision in the model express
the inconformity of the attribute setting of column.
Solving strategy: users make sure the scope and
precision according to the need of statistical
analysis, and get rid of noise data.
(5) The description of constraints conflict
Description: related objects equivalent data
elements have different examples constraint. Such as
the age of the adult in the tableT1 must be over 18
years old, and it is above 20 years old in the table
T2.
The form of the relation model conflict; the
relevant for the element in the relation bag and
constraint is based on the constraints of the element.
Such as the relevance of the column and constraint,
the attribute of constraint .body is above 18 years
old .which means examples must be above 18.In the
model, the constraints conflict is the same element
of the expression conflict which is based on the
constraint.
Solving strategy: matching the same element,
which is relevant for the constraint, if the relevant
expression is different, users decide whether it has
constraints conflict and conflict resolution or the
conflict solved by user is only the constraints
conflict which is possible to occur. The specific
expression meaning is solved by users.
(6) The primary key conflicts
Description; Established in related objects of
different only marks. Such as, the primary key is
numbers which is in the table T1 (numbers, years,
trade … ),the primary key is trade in the table T2
YEARBOOK DATA INTEGRATION BASED ON COMMON WAREHOUSE MODEL
571