DSRG.VKB
Class VKB

java.lang.Object
  |
  +--DSRG.VKB.VKB

public class VKB

extends java.lang.Object

implements java.io.Serializable, VSA_VKB

This VKB class represents the VKB of EVE system.
It stores a hashtable of View_index.
We find the view definitiosn by name is by traverse

List of Functions VKB should provide

• VKB Overall Functions
• Add one View Definition
• remove one View Definition
• Search View Definition by View Name
• Search View Definitions by IS name
• Search View Definitions by Relation name
• Search View Definitions by Attribute name
• Modify View Component of Specifice View Definition. We should provide all the functions of getting and setting the View Component attributes.
• Bulk Loading a VKB from a ESQL/SQL file.
• View Definition Overall Functions, please reference View_Definition Document

VKB should help VSA in the view synchronization. Now, in VSA we can do following schema evolutions:

• Delete Relation
• Delete Attribute
• Change Relation Name
• Change Attribute Name

I put some feature to MKB to let it help us do the Change Name functions. I do that by putting a reference of that object in MKB at every place where need a name. That's makes the changing name functions simple, but that increase the coupling between MKB and VKB. The reason why I select this strategy is that the Changing Name functions will affect both MKB and VKB anyway. That means, If we seperate the storage of name in the MKB and VKB, we still need another function to call both parts to change name synchronized. That will need a lot of more work. As well, because I specify the VKB/MKB interface in "interface" VKB_MKB, we can easily know how can VKB access MKB. Sure, if we want to use Relation and Attribute classes in MKB, we need to know the knowledge of them. I think that's the only drawback.

I try to do all the class design to help us make the implementation extendable. So, if in the future MKB needs to be changed, and that change will affect the Relation and Attribute classes in MKB, like MKB change its structure to keep the history, we just need to remain the same interface between VKB and those classes, then everything should be fine. I need to define another two interfaces between VKB and Relation and Attribute.

See Also:

View_Definition, Serialized Form

Field Summary

(package private) MKB	mkb The reference of MKB this VKB based on.
(package private) java.util.Hashtable	View_index Index of view definition on View Name.

Constructor Summary

VKB()
Default constructor.

VKB(java.lang.String ESQL_file, MKB ref)
Parse E-SQL/SQL String and create the VKB object.

Method Summary

void	addViewDefinition(View_Definition newVD) Add one view definition to this VKB It will affect the index structure.
void	changeAttributeName(java.lang.String IS_name, java.lang.String Rel_name, java.lang.String Attr_name, java.lang.String new_name) This function will call MKB to change the specific attribute.
void	changeRelationName(java.lang.String IS_name, java.lang.String Rel_name, java.lang.String new_name) This function will call MKB to change the specific relation.
void	dropSetOfVDs(java.util.Vector VDs) Drop a vector of view definitions specified by Vector VDs.
void	dropViewDefinition(java.lang.String viewName) Remove one view definition from this VKB with specific view name.
void	dropViewDefinition(View_Definition view) Remove one view definition from this VKB.
java.lang.String	getESQL(java.lang.String viewName) returns the E-SQl definition fo the view with the given name
MKB	getMKB() Get the MKB of this VKB
java.lang.String	getSQL(java.lang.String viewName) returns the SQl definition fo the view with the given name
View_Definition	getVD(java.lang.String view_name) Get View Definition for a View of a specific name
java.util.Vector	getViewDefinitions(java.lang.String IS_name) Get a vector of ViewDefinitions mentioning a specific Information Source (IS) name.
java.util.Vector	getViewDefinitions(java.lang.String IS_name, java.lang.String Rel_name) Get a vector of all ViewDefinitions mentioning a Relation of a specific Relation Name.
java.util.Vector	getViewDefinitions(java.lang.String IS_name, java.lang.String Rel_name, java.lang.String Attr_name) Get a vector of ViewDefinitions mentioning an Attribute of the given name.
java.util.Vector	getViewNames() Get a Vector of ViewNames in this VKB
void	replaceViewDefinition(View_Definition V, View_Definition bestV) Replace view V with bestV.
void	setMKB(MKB ref) Set the MKB of this VKB
void	setViewIndex(java.util.Hashtable index) Set View_Index Hashtable of this VKB
java.lang.String	toString() Display VKB in ESQL mode

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, wait, wait, wait

Field Detail

View_index

java.util.Hashtable View_index

Index of view definition on View Name.

mkb

MKB mkb

The reference of MKB this VKB based on.

Constructor Detail

VKB

public VKB()

Default constructor.

VKB

public VKB(java.lang.String ESQL_file,
           MKB ref)

Parse E-SQL/SQL String and create the VKB object.

Parameters:

ESQL_file - E-SQL/SQL of this VKB/ or a file name

ref - MKB of this VKB depends on

Method Detail

getMKB

public MKB getMKB()

Get the MKB of this VKB

setMKB

public void setMKB(MKB ref)

Set the MKB of this VKB

replaceViewDefinition

public void replaceViewDefinition(View_Definition V,
                                  View_Definition bestV)

Replace view V with bestV. This is the place to update the view definition after selection. MAYA

Specified by:

replaceViewDefinition in interface VSA_VKB

setViewIndex

public void setViewIndex(java.util.Hashtable index)

Set View_Index Hashtable of this VKB

Parameters:

index - New index of view definitions

addViewDefinition

public void addViewDefinition(View_Definition newVD)

Add one view definition to this VKB

It will affect the index structure. We need to re-index the View definition.

dropViewDefinition

public void dropViewDefinition(java.lang.String viewName)

Remove one view definition from this VKB with specific view name.

It will affect the index structure. We need to re-index the View definition.

dropViewDefinition

public void dropViewDefinition(View_Definition view)

Remove one view definition from this VKB.

It will affect the index structure. We need to re-index the View definition.

dropSetOfVDs

public void dropSetOfVDs(java.util.Vector VDs)

Drop a vector of view definitions specified by Vector VDs.

Specified by:

dropSetOfVDs in interface VSA_VKB

getViewDefinitions

public java.util.Vector getViewDefinitions(java.lang.String IS_name)

Get a vector of ViewDefinitions mentioning a specific Information Source (IS) name.

Returns:

null: No View Definition affected by this IS, Vector: View Definitions affected by this IS.

getViewDefinitions

public java.util.Vector getViewDefinitions(java.lang.String IS_name,
                                           java.lang.String Rel_name)

Get a vector of all ViewDefinitions mentioning a Relation of a specific Relation Name.

Specified by:

getViewDefinitions in interface VSA_VKB

Parameters:

IS_name - Information Source Name

Rel_name - Relation Name

Returns:

null: No View Definition affected, Vector: View Definitions affected by relation

getViewDefinitions

public java.util.Vector getViewDefinitions(java.lang.String IS_name,
                                           java.lang.String Rel_name,
                                           java.lang.String Attr_name)

Get a vector of ViewDefinitions mentioning an Attribute of the given name.

Specified by:

getViewDefinitions in interface VSA_VKB

Parameters:

IS_name - Information Source Name

Rel_name - Relation Name

Attr_name - Attribute Name

Returns:

null: No View Definition affected, Vector: View Definitions affected by attribute

getESQL

public java.lang.String getESQL(java.lang.String viewName)

returns the E-SQl definition fo the view with the given name

Parameters:

viewName - the name of the view to be queried

Returns:

E-SQL view definition or empty String object

getSQL

public java.lang.String getSQL(java.lang.String viewName)

returns the SQl definition fo the view with the given name

Parameters:

viewName - the name of the view to be queried

Returns:

SQL view definition or empty String object

getVD

public View_Definition getVD(java.lang.String view_name)

Get View Definition for a View of a specific name

Parameters:

view_name - name of view definition

Returns:

View_Definition or null.

changeAttributeName

public void changeAttributeName(java.lang.String IS_name,
                                java.lang.String Rel_name,
                                java.lang.String Attr_name,
                                java.lang.String new_name)

This function will call MKB to change the specific attribute. It will change all the view_components in all view definitions in VKB from one attribute name to another name.

It's different from make one attribute_component in one view_definition reference to another attribute, which will only change one attribute_component of one view_definition.

Parameters:

IS_name - Information Source Name

Rel_name - Relation Name

Attr_name - Attribute Name

new_name - New attribute Name

changeRelationName

public void changeRelationName(java.lang.String IS_name,
                               java.lang.String Rel_name,
                               java.lang.String new_name)

This function will call MKB to change the specific relation. It will change all hte view_components in all view definitions in VKB from one relation name to another name.

It's means it will also affect the attribute_component and condition_component.

Parameters:

IS_name - Information Source Name

Rel_name - Relation Name

new_name - New Relation Name

getViewNames

public java.util.Vector getViewNames()

Get a Vector of ViewNames in this VKB

Returns:

null no view stores; else return a vector of view names.

toString

public java.lang.String toString()

Display VKB in ESQL mode

Overrides:

toString in class java.lang.Object