Okay, and how do you access it?

If you have journaling enabled, you can parse them.

Are you in %SYS namespace? Underlying database (CACHELIB) is probably mounted as read-only.

12th piece is the FreezeOnError property for a Database and is always set to on (since 2008.1.0.217.0). The corresponding property FreezeOnError was removed from SYS.Database class.

Check where in ParseZU49Info it takes field 14 and what property does it fills with that information.  Check %syDatabase.inc for more information.

#; Pieces of return value from $zu(49)
#define mountpiece 1
#define blksizpiece 2
#define uicpiece 3
#define filsizpiece 4
#define expandpiece 5
#define maxblkpiece 6
#define glodirpiece 7
#define gloptrpiece 8
#define rdirpiece 9
#define rgrpiece 10
#define glogrpiece 11
#define freezepiece 12
#define colpiece 13
#define sfnpiece 14
#define totvolpiece 15
#define formatpiece 16
#define attribpiece 17
#define statuspiece 18
#define exptimepiece 19
#define nojrnpiece 20
#define bigdbpiece 21
#define curblkspiece 22
#define blkspermappiece 23
#define curmapspiece 24
#define resourcepiece 25
#define enckeyidpiece 26

ParseZU49Info method in SYS.Database class translates $ZU(49) call into SYS.Database properties.

Okay, then you need to use your original storage definition, but when selecting invalid, select it in a NVL function:

SELECT
ID, Code, Description, NVL(Invalid, 0)
FROM Wendy.LTCodes

It should return 0 instead of empty string.

Runtime Variables are for that purpose.

And if you want to apply filter to any MDX query against a cube, you can specify a %OnGetFilterSpec callback.

These changes fixed it:

• Removed highlited part of storage definition
• Made invalid property Transient
• Added 0 default to $Get

Class Wendy.LTCodes Extends %Persistent [ StorageStrategy = LTCStorage ]
{

Property Code As %String;

Property Description As %String;

Property Invalid As %Library.Boolean [ SqlComputeCode = { set {*} = ##class(Wendy.LTCodes).GetInvalid({Code})}, SqlComputed, Transient ];

Index CodeIndex On Code [ IdKey, PrimaryKey, Unique ];

ClassMethod GetInvalid(WSCode) As %Boolean
{
    Quit $G(^LTCODES(WSCode,"INVALID"),0)
}

Method InvalidGet() As %Boolean
{
    Quit ..GetInvalid(i%Code)
}

Method InvalidSet(value As %Boolean) As %Status
{
    Set ^LTCODES(i%Code,"INVALID")=value
    quit $$$OK
}

/// Do ##class(Wendy.LTCodes).SetData()
ClassMethod SetData()
{
    kill ^LTCODES
    S ^LTCODES("N001")="ANYOLD DESC"
    S ^LTCODES("N001","INVALID")=1
    S ^LTCODES("N002")="C5 REPEAT 1"
    S ^LTCODES("N111")="SPECIMEN COMMENT"
    S ^LTCODES("N200")="MSUD SCREEN|MSUD"
    S ^LTCODES("N500")="Sickle Cell Screen"
}

Storage LTCStorage
{
<SQLMap name="LTCMap">
<Data name="Description">
<Delimiter>"|"</Delimiter>
<Piece>1</Piece>
</Data>
<Global>^LTCODES</Global>
<Subscript name="1">
<Expression>{Code}</Expression>
</Subscript>
<Type>data</Type>
</SQLMap>
<StreamLocation>^Wendy.LTCodesS</StreamLocation>
<Type>%CacheSQLStorage</Type>
}

}

You can define a property of  %Stream.Object class and store %Stream.FileBinary/%Stream.FileCharacter there.

I removed InvalidGet method and object access to the property stopped working.

Class Utils.GlobalProp Extends %Persistent
{

Parameter InvalidGLVN = "^Utils.GlobalPropP";

Property Invalid As %String [ SqlComputeCode = {set {*} = ##class(Utils.GlobalProp).InvalidStatic()}, SqlComputed, Transient ];

ClassMethod InvalidStatic() As %String
{
    Return $Get(@..#InvalidGLVN)
}

Method InvalidSet(val As %String) As %Status
{
    Set @..#InvalidGLVN = val
    Return $$$OK
}

/// Do ##class(Utils.GlobalProp).Test()
ClassMethod Test()
{
    Do ..%KillExtent()
    Set obj = ..%New()
    Write "Invalid old: " _ obj.Invalid,!
    Set obj.Invalid = $Random(100)
    Write "Invalid new: " _ obj.Invalid,!
    Do obj.%Save()
    Kill obj
    &sql(SELECT Invalid INTO :invalid FROM Utils.GlobalProp WHERE Id = 1)
    Write "SQLCODE: " _ SQLCODE,!
    Write "Invalid sql: " _ invalid,!
}

Outputs:

Invalid old:
Invalid new:
SQLCODE: 0
Invalid sql: 65

Related Int code:

zInvalidCompute(%id)
    New %tException,%val set %val = ""
    try {
    set %val = ##class(Utils.GlobalProp).InvalidStatic()
    } catch %tException { throw %tException }
    Quit %val
zInvalidGet() public {
    If i%Invalid = "" { Set ..Invalid=..InvalidCompute($listget(i%"%%OID")) } Quit i%Invalid }
zInvalidSQLCompute()
    // Compute code for field Invalid
 set %d(2) = ##class(Utils.GlobalProp).InvalidStatic()
 QUIT

    Do $System.Status.DisplayError(tStatus)
        Write !
    }
    Quit
}
}