I am using the Ada library gnatcoll.sql to create parametrizable SQL queries.

While I am able to create Integer parameters for type SQL_Field_Integer using the function:

function Integer_Param (Index : Positive) return Integer_Fields.Field'Class
  renames Integer_Fields.Param;

As well as for the following types using their respective functions:

SQL_Field_Bigint, SQL_Field_Text, SQL_Field_Boolean, SQL_Field_Float, SQL_Field_Long_Float, SQL_Field_Money, SQL_Field_Time, SQL_Field_Date

I am not able to parametrize Blob fields, I don't find those type mappings nor any service except the postgresql/sqlite bindings at low-level.

How can I parametrize blob types? As String?