Metadata Property Mappings using PowerShell

Note: BDC Category, Check the Category Name in your Search Service App, i.e "Business Data"

Note: For PropSet --> edit the crawled property and get "Property Set ID"

$searchapp = Get-SPEnterpriseSearchServiceApplication "Search Service Application"

$category = Get-SPEnterpriseSearchMetadataCategory –Identity "SharePoint" -SearchApplication $searchapp

$crawledproperty = New-SPEnterpriseSearchMetadataCrawledProperty -SearchApplication $searchapp -Category $category -VariantType 31 -PropSet "00130329-0000-0130-c000-000000131346" -Name ows_TestProperty1 -IsNameEnum $false

$managedproperty = New-SPEnterpriseSearchMetadataManagedProperty -SearchApplication $searchapp -Name TestProperty1 -Type 1

New-SPEnterpriseSearchMetadataMapping -SearchApplication $searchapp -ManagedProperty $managedproperty -CrawledProperty $crawledproperty

DATA TYPE	CRAWLED PROPERTY VARIANTTYPE	MANAGED PROPERTY –TYPE PARAMETER
Text	31	1
Integer	20	2
Decimal	5	3
Date and Time	64	4
Yes/No	11	5
Binary Data	65	6