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· Dec 17, 2015

API equivalent to 'Recreate a database' option in ^DATABASE routine?

#Databases #System Administration #Caché

Hi,

Is there any API equivalent (within Config.Databases class, or elsewhere) that has the same functionality as the 'Recreate a database' option in the ^DATABASE routine?

This option was added to ^DATABASE (according to internal Devlog CFL1263):

to recreate a database which is equivalent to deleting the .DAT file and recreating it.

I tested this, and the recreate option also appears to also preserve the original database parameters (e.g. max size, resource name).  But when I separately try Delete, and then Create, it does not preserve those settings, so the 'Recreate' option provides additional functionality. 

Is there a way to accomplish this programmatically through a supported API, other than scripting the ^DATABASE routine?

Thanks,

Steve

Discussion (2)1
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Timothy Leavitt · Dec 17, 2015

I think SYS.Database (in %SYS), rather than Config.Databases, can accomplish what you want. Particularly, you can open an object representing a database, call its Delete() method, and then call %Save() on it. That seems to have the same effect you're looking for.

Here's a sample class (Demo.Recreate):

Include %occInclude

Class Demo.Recreate
{

ClassMethod Run(pDBDirectory As %String)
{
    new $Namespace
    zn "%SYS"
    try {    
        //Get the database
        set tDB = ##class(SYS.Database).%OpenId(pDBDirectory)
        If '$IsObject(tDB) {
            $$$ThrowStatus($$$ERROR($$$GeneralError,"Database "_pDBDirectory_" not found."))
        }
        
        write !,"Properties of database:",!
        zw tDB
        
        write !
        
        //For demonstration purposes: show contents of a global in that DB
        for i=1:1:10 {
            set ^["^^"_pDBDirectory]demo(i) = i
        }
        write "Contents of ^[""^^"_pDBDirectory_"""]demo: ",!
        zw ^["^^"_pDBDirectory]demo
        
        write !
        
        write "Deleting database..."
        $$$THROWONERROR(tSC,tDB.Delete())
        write " done.",!
        write "Recreating database..."
        $$$THROWONERROR(tSC,tDB.%Save())
        write " done.",!
        
        write !
        
        write !,"Properties of database:",!
        zw tDB
        
        write !
        
        //For demonstration purposes: show that contents of global in that DB are gone
        write "Contents of ^[""^^"_pDBDirectory_"""]demo: ",!
        zw ^["^^"_pDBDirectory]demo
        
        zw tDB
    } catch anyException {
        write anyException.DisplayString(),!
    }
}

}

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