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Evgeny Shvarov
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Question Evgeny Shvarov · Jun 9, 2017

Caché Classes: How to Make a View on a Class to Manage Property Level Security?

#Caché #Data Model #Object Data Model #Security

Hi, Community!

Suppose I have class A with properties P1 and P2.

I want to introduce class B, which would have same records as Class A, but only  one property - P2.

What is the easiest  way to manage it assuming that I would like to use Class A to add records and be available for any operations to Users with Role A.

And I would like to introduce class B for Users with role B for read-only access.  Preferably they shouldn't even be aware of Class A and P1 existence .

What is the easiest way to introduce it and manage it?

Use some proxy-classes?  Property-level security?

Or to Introduce usual class B with only property P2 and manage the update operations together with Class A?

Discussion (10)1
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Comments

Evgeny Shvarov  Jun 9, 2017 to Eduard Lebedyuk

VIews work for SQL access. I really need a kind of view, but for classes paradigm: so I could have access to Class B property P2 with Caché object access.

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Evgeny Shvarov  Jun 9, 2017 to Vitaliy Serdtsev

Thanks, Vitaly!

That looks exactly like what I want. I'll give it a try. Except with not very clear magic with SQLStorage. 

Is there any way to "generate" compatible storage? And why SQLStorage? Why not default CachéStorage, but copy-pasted from Class A?

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Vitaliy Serdtsev · Jun 9, 2017

If you only need SQL access, then will be easier to create a view (CREATE VIEW), if need both, then - %CacheSQLStorage, e.g.:

<FONT COLOR="#000080">Class demo.A Extends %Persistent
</FONT><FONT COLOR="#000000">{

</FONT><FONT COLOR="#000080">Property </FONT><FONT COLOR="#000000">P1;
</FONT><FONT COLOR="#000080">Property </FONT><FONT COLOR="#000000">P2;
</FONT><FONT COLOR="#000080">ClassMethod </FONT><FONT COLOR="#000000">Fill()
{
  </FONT><FONT COLOR="#0000ff">d </FONT><FONT COLOR="#000000">..</FONT><FONT COLOR="#0000ff">%KillExtent</FONT><FONT COLOR="#000000">()
  
  </FONT><FONT COLOR="#0000ff">f </FONT><FONT COLOR="#800000">i</FONT><FONT COLOR="#000000">=1:1:3 </FONT><FONT COLOR="#800080">{
    </FONT><FONT COLOR="#0000ff">s </FONT><FONT COLOR="#800000">t</FONT><FONT COLOR="#000000">=..</FONT><FONT COLOR="#0000ff">%New</FONT><FONT COLOR="#000000">()
    </FONT><FONT COLOR="#0000ff">s </FONT><FONT COLOR="#800000">t</FONT><FONT COLOR="#000000">.</FONT><FONT COLOR="#0000ff">P1</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"P1_"</FONT><FONT COLOR="#000000"></FONT><FONT COLOR="#800000">i
    </FONT><FONT COLOR="#0000ff">s </FONT><FONT COLOR="#800000">t</FONT><FONT COLOR="#000000">.</FONT><FONT COLOR="#0000ff">P2</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"P2"</FONT><FONT COLOR="#000000">_</FONT><FONT COLOR="#800000">i
    </FONT><FONT COLOR="#0000ff">d </FONT><FONT COLOR="#800000">t</FONT><FONT COLOR="#000000">.</FONT><FONT COLOR="#0000ff">%Save</FONT><FONT COLOR="#000000">()
  </FONT><FONT COLOR="#800080">}
</FONT><FONT COLOR="#000000">}
</FONT><FONT COLOR="#000080">Storage </FONT><FONT COLOR="#000000">Default
{
<<FONT COLOR="#000080">Data </FONT><FONT COLOR="#800000">name</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"ADefaultData"</FONT><FONT COLOR="#000000">>
  <</FONT><FONT COLOR="#000080">Value </FONT><FONT COLOR="#800000">name</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"1"</FONT><FONT COLOR="#000000">>
    <</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>%%CLASSNAME</</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>
  </</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>
  <</FONT><FONT COLOR="#000080">Value </FONT><FONT COLOR="#800000">name</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"2"</FONT><FONT COLOR="#000000">>
    <</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>P1</</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>
  </</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>
  <</FONT><FONT COLOR="#000080">Value </FONT><FONT COLOR="#800000">name</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"3"</FONT><FONT COLOR="#000000">>
    <</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>P2</</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>
  </</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>
</</FONT><FONT COLOR="#000080">Data</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">DataLocation</FONT><FONT COLOR="#000000">>^demo.AD</</FONT><FONT COLOR="#000080">DataLocation</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">DefaultData</FONT><FONT COLOR="#000000">>ADefaultData</</FONT><FONT COLOR="#000080">DefaultData</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">IdLocation</FONT><FONT COLOR="#000000">>^demo.AD</</FONT><FONT COLOR="#000080">IdLocation</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">IndexLocation</FONT><FONT COLOR="#000000">>^demo.AI</</FONT><FONT COLOR="#000080">IndexLocation</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">StreamLocation</FONT><FONT COLOR="#000000">>^demo.AS</</FONT><FONT COLOR="#000080">StreamLocation</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">Type</FONT><FONT COLOR="#000000">>%Library.CacheStorage</</FONT><FONT COLOR="#000080">Type</FONT><FONT COLOR="#000000">>
</FONT>}
}</FONT>
<FONT COLOR="#000080">Class demo.B Extends %Persistent </FONT><FONT COLOR="#000000">[ </FONT><FONT COLOR="#000080">Final</FONT><FONT COLOR="#000000">, </FONT><FONT COLOR="#000080">StorageStrategy </FONT><FONT COLOR="#000000">= Default ]
{
</FONT><FONT COLOR="#000080">Parameter </FONT><FONT COLOR="#000000">READONLY = </FONT><FONT COLOR="#000080">1</FONT><FONT COLOR="#000000">;
</FONT><FONT COLOR="#000080">Property </FONT><FONT COLOR="#000000">P2;
</FONT><FONT COLOR="#000080">Storage </FONT><FONT COLOR="#000000">Default
{
<<FONT COLOR="#000080">SQLMap </FONT><FONT COLOR="#800000">name</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"BDefaultData"</FONT><FONT COLOR="#000000">>
  <</FONT><FONT COLOR="#000080">Data </FONT><FONT COLOR="#800000">name</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"P2"</FONT><FONT COLOR="#000000">>
    <</FONT><FONT COLOR="#000080">Piece</FONT><FONT COLOR="#000000">>3</</FONT><FONT COLOR="#000080">Piece</FONT><FONT COLOR="#000000">>
  </</FONT><FONT COLOR="#000080">Data</FONT><FONT COLOR="#000000">>
  <</FONT><FONT COLOR="#000080">Global</FONT><FONT COLOR="#000000">>^demo.AD</</FONT><FONT COLOR="#000080">Global</FONT><FONT COLOR="#000000">>
  <</FONT><FONT COLOR="#000080">RowIdSpec </FONT><FONT COLOR="#800000">name</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"1"</FONT><FONT COLOR="#000000">>
    <</FONT><FONT COLOR="#000080">Expression</FONT><FONT COLOR="#000000">>{L1}</</FONT><FONT COLOR="#000080">Expression</FONT><FONT COLOR="#000000">>
    <</FONT><FONT COLOR="#000080">Field</FONT><FONT COLOR="#000000">>ID</</FONT><FONT COLOR="#000080">Field</FONT><FONT COLOR="#000000">>
  </</FONT><FONT COLOR="#000080">RowIdSpec</FONT><FONT COLOR="#000000">>
  <</FONT><FONT COLOR="#000080">Subscript </FONT><FONT COLOR="#800000">name</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"1"</FONT><FONT COLOR="#000000">>
    <</FONT><FONT COLOR="#000080">Expression</FONT><FONT COLOR="#000000">>{ID}</</FONT><FONT COLOR="#000080">Expression</FONT><FONT COLOR="#000000">>
  </</FONT><FONT COLOR="#000080">Subscript</FONT><FONT COLOR="#000000">>
  <</FONT><FONT COLOR="#000080">Type</FONT><FONT COLOR="#000000">>data</</FONT><FONT COLOR="#000080">Type</FONT><FONT COLOR="#000000">>
</</FONT><FONT COLOR="#000080">SQLMap</FONT><FONT COLOR="#000000">></FONT>
<<FONT COLOR="#000080">StreamLocation</FONT><FONT COLOR="#000000">>^demo.AS</</FONT><FONT COLOR="#000080">StreamLocation</FONT><FONT COLOR="#000000">></FONT>
<<FONT COLOR="#000080">Type</FONT><FONT COLOR="#000000">>%CacheSQLStorage</</FONT><FONT COLOR="#000080">Type</FONT><FONT COLOR="#000000">></FONT>
}
}</FONT>
Result:
USER><FONT COLOR="#0000ff">d </FONT><FONT COLOR="#000080">##class</FONT><FONT COLOR="#000000">(</FONT><FONT COLOR="#008080">demo.A</FONT><FONT COLOR="#000000">).</FONT><FONT COLOR="#0000ff">Fill</FONT><FONT COLOR="#000000">()</FONT>

USER><FONT COLOR="#0000ff">d $SYSTEM</FONT><FONT COLOR="#008080">.SQL</FONT><FONT COLOR="#000000">.</FONT><FONT COLOR="#0000ff">Shell</FONT><FONT COLOR="#000000">()</FONT>
SQL Command Line Shell
The command prefix is currently set to: <>.
Enter q to quit, ? for help.
USER>><FONT COLOR="#0000ff">select </FONT><FONT COLOR="#000080">* from </FONT><FONT COLOR="#008000">demo</FONT><FONT COLOR="#000000">.</FONT><FONT COLOR="#008000">A</FONT>
  1.  select * from demo.A

ID      P1      P2
1       P1_1    P2_1
2       P1_2    P2_2
3       P1_3    P2_3
3 Rows(s) Affected
statement prepare time(s)/globals/lines/disk: 0.1426s/46110/260143/45ms
execute time(s)/globals/lines/disk: 0.0004s/16/809/0ms
cached query class: %sqlcq.USER.cls12
USER>><FONT COLOR="#0000ff">select </FONT><FONT COLOR="#000080">* from </FONT><FONT COLOR="#008000">demo</FONT><FONT COLOR="#000000">.</FONT><FONT COLOR="#008000">B</FONT>
2.      select * from demo.B
ID      P2
1       P2_1
2       P2_2
3       P2_3
3 Rows(s) Affected
statement prepare time(s)/globals/lines/disk: 0.0696s/44550/243602/0ms
execute time(s)/globals/lines/disk: 0.0002s/4/619/0ms
cached query class: %sqlcq.USER.cls13
USER>>quit
USER><FONT COLOR="#0000ff">w </FONT><FONT COLOR="#000080">##class</FONT><FONT COLOR="#000000">(</FONT><FONT COLOR="#008080">demo.B</FONT><FONT COLOR="#000000">).</FONT><FONT COLOR="#0000ff">%OpenId</FONT><FONT COLOR="#000000">(3).</FONT><FONT COLOR="#0000ff">P2</FONT>
P2_3
0
Vitaliy Serdtsev  Jun 9, 2017 to Evgeny Shvarov
Is there any way to "generate" compatible storage? And why SQLStorage? Why not default CachéStorage, but copy-pasted from Class A?
Unfortunately, to use %CacheStorage will not work, since at compile occurs the error:
ERROR #5564: Storage reference: '^demo.AD' used in 'demo.B.cls' is already registered for use by 'demo.A.cls'
  > ERROR #5030: An error occurred while compiling class 'demo.B'
0
Vitaliy Serdtsev  Jun 9, 2017 to Eduard Lebedyuk

Indeed, thank you:

<FONT COLOR="#000080">Class demo.B Extends %Persistent </FONT><FONT COLOR="#000000">[ </FONT><FONT COLOR="#000080">Final </FONT><FONT COLOR="#000000">]
{

</FONT><FONT COLOR="#000080">Parameter </FONT><FONT COLOR="#000000">MANAGEDEXTENT </FONT><FONT COLOR="#000080">As </FONT><FONT COLOR="#000000">INTEGER [ </FONT><FONT COLOR="#000080">Constraint </FONT><FONT COLOR="#000000">= </FONT><FONT COLOR="#800080">"0,1"</FONT><FONT COLOR="#000000">, </FONT><FONT COLOR="#000080">Flags </FONT><FONT COLOR="#000000">= ENUM ] = </FONT><FONT COLOR="#000080">0</FONT><FONT COLOR="#000000">;
</FONT><FONT COLOR="#000080">Parameter </FONT><FONT COLOR="#000000">READONLY = </FONT><FONT COLOR="#000080">1</FONT><FONT COLOR="#000000">;
</FONT><FONT COLOR="#000080">Property </FONT><FONT COLOR="#000000">P2;
</FONT><FONT COLOR="#000080">Storage </FONT><FONT COLOR="#000000">Default
{
<<FONT COLOR="#000080">Data </FONT><FONT COLOR="#800000">name</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"BDefaultData"</FONT><FONT COLOR="#000000">>
  <</FONT><FONT COLOR="#000080">Value </FONT><FONT COLOR="#800000">name</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#008000">"3"</FONT><FONT COLOR="#000000">>
    <</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>P2</</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>
  </</FONT><FONT COLOR="#000080">Value</FONT><FONT COLOR="#000000">>
</</FONT><FONT COLOR="#000080">Data</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">DataLocation</FONT><FONT COLOR="#000000">>^demo.AD</</FONT><FONT COLOR="#000080">DataLocation</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">DefaultData</FONT><FONT COLOR="#000000">>BDefaultData</</FONT><FONT COLOR="#000080">DefaultData</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">IdLocation</FONT><FONT COLOR="#000000">>^demo.AD</</FONT><FONT COLOR="#000080">IdLocation</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">IndexLocation</FONT><FONT COLOR="#000000">>^demo.AI</</FONT><FONT COLOR="#000080">IndexLocation</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">StreamLocation</FONT><FONT COLOR="#000000">>^demo.AS</</FONT><FONT COLOR="#000080">StreamLocation</FONT><FONT COLOR="#000000">>
<</FONT><FONT COLOR="#000080">Type</FONT><FONT COLOR="#000000">>%Library.CacheStorage</</FONT><FONT COLOR="#000080">Type</FONT><FONT COLOR="#000000">></FONT>
}
}</FONT>
0
Amir Samary  Jun 10, 2017 to Eduard Lebedyuk

You are right Eduard. Column level security would be enough. It is even simpler!

0
Amir Samary · Jun 9, 2017

Hi!

It looks like you are trying to implement security on your class model instead of just configuring it. I think you only need a single class with all the properties. Then you will give user A full access to the table by configuring this user on a Role that gives him INSERT, DELETE, UPDATE, SELECT privileges. 

User B would be assigned to another role that would give it SELECT privilege only.

And if User B can only see a subset of columns from your table, then configure row level security using the Role information on $Role. InterSystems documentation here explains row level security configuration very clearly.

0