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Eduard Lebedyuk · Jul 17, 2017

It depends on the signing method.  I'd try to sign a stream without new lines at all.

Do you know if openssl uses the line-end to know up the where to sign and does it line by line, or does it include the line endings in the value that should be signed?

openssl signs incoming byte stream, not a character stream, so there's no distinction.

Eduard Lebedyuk · Jul 16, 2017

It depends on a queries you want to run. For example you want to get all parents' ids which have a child with a specific property value. In a child class you can index for one or several properties, and execute this query:

SELECT parentId
FROM child
WHERE propertyA = 'value'

Documentation on indexes.

Or you can define a computed property in your parent class and index that.

Eduard Lebedyuk · Jul 14, 2017

When you define a query:

Query MyQuery() As %Query
{
  QUERY TEXT
}

Or

Query MyQuery() As %SQLQuery
{
  QUERY TEXT
}

That means that this query implements an interface provided by %Library.Query or %Library.SQLQuery respectively. They define method generators for Fetch/Execute/Func methods (more on them). Each method of the interface class gets called during compilation

You can subclass %Library.Query or %Library.SQLQuery to define your own methods. Here's custom query interface that does 2 things:

  • Changes ROWSPEC to Id123:%String
    • It can be seen in class definition after compilation
    • <QueryName>GetInfo and <QueryName>GetODBCInfo methods also reflect new ROWSPEC properly
  • Generates <QueryName>GetText method that returns query text
Class Utils.MyQuery Extends %SQLQuery
{

/// This method would be ran before others and changes ROWSPEC to "Id123:%String"
ClassMethod %ChangeRowspec() [ CodeMode = objectgenerator, ServerOnly = 1 ]
{
    // quit if we're not compiling a query
    if %mode="method" quit $$$OK
    
    set class = %class.Name
    set query = %compiledmethod.parent.Name        
    set rowspec = "Id123:%String"
    
    // Modify query definition
    $$$defSubMemberSet(class,$$$cCLASSquery,query,$$$cQUERYparameter,"ROWSPEC",rowspec)
    
    // Modify compiled query definition
    $$$comSubMemberSet(class,$$$cCLASSquery,query,$$$cQUERYparameter,"ROWSPEC",rowspec)
    
    // Update compile-time parameter value
    set %parameter("ROWSPEC") = rowspec
    
    // Update class definition
    do UpdClsDef^%occLibrary(class)
    
    quit $$$OK
}

/// GetText is a method that is used to get query text as a %String
ClassMethod GetText() As %String [ CodeMode = objectgenerator, ServerOnly = 1 ]
{
    if %mode="method" quit $$$OK
    $$$comMemberKeyGetLvar(query,%classname,$$$cCLASSquery,%property,$$$cQUERYsqlquery)
    do %code.WriteLine("    quit " _ $$$quote(query))
    quit $$$OK
}

}

And here's a test class with our new query:

Class Utils.MyQueryTest
{
Query ABC() As Utils.MyQuery
{
SELECT 1
}
}

After Utils.MyQueryTest is compiled it looks like this:

Class Utils.MyQueryTest
{
Query ABC() As Utils.MyQuery(ROWSPEC = "Id123:%String")
{
SELECT 1
}
}

You can modify this interface to get any behavior you want.

Code is available on GitHub.

Eduard Lebedyuk · Jul 12, 2017

what is ExtentFunc?

For each persistent class there is an Extent class query that returns IDs.

For Sample.Employee class it is:

SELECT ID, Name, SSN, Home_City, Home_State FROM Sample.Employee

For each class query, <QueryName>Func  method gets generated.

You can see it in the class int code using  Show Other View (Open Sample.Employee and press Ctrl+Shift+V).

Here's the generated <QueryName>Func  method for the Extent query of the Sample.Employee class:

zExtentFunc() public {
    try {
        set tSchemaPath = ##class(%SQL.Statement).%ClassPath($classname())
            set tStatement = ##class(%SQL.Statement).%New(,tSchemaPath)
            do tStatement.prepare(" SELECT ID , Name , SSN , Home_City , Home_State FROM Sample . Employee")
        set tResult = tStatement.%Execute()
    }
    catch tException { if '$Isobject($Get(tResult)) { set tResult = ##class(%SQL.StatementResult).%New() } set tResult.%SQLCODE=tException.AsSQLCODE(),tResult.%Message=tException.AsSQLMessage() }
    Quit tResult }

It executes the query and returns result set. More on class queries.

 

class %sqlcq.SAMPLES.cls9

To see the code:

  • Go to General SQL settings in SMP and set Cached Query - Save Source to Yes.
  • Purge cached queries from sample namespace.
  • Execute this query again.
  • Check the new query class name- probably  %sqlcq.SAMPLES.cls1
  • It now could be seen in studio
Eduard Lebedyuk · Jul 11, 2017

Sample.Company and Sample.Employee share one company/many employees relationship.

Do you want to iterate over employees and display a company name for each?

set rs = ##class(Sample.Employee).ExtentFunc()
while rs.%Next() { set emp = ##class(Sample.Employee).%OpenId(rs.ID) w emp.Company.Name,! }

You can even get company names even without opening objects:

set rs = ##class(Sample.Employee).ExtentFunc()
while rs.%Next() { w ##class(Sample.Company).NameGetStored(##class(Sample.Employee).CompanyGetStored(rs.ID)),! }