Manipulate score by field integer value

[frankmehlhop.com (Frank)]

I use Elastic for searching pdf's. One of the fields apart of the pdf-content is doridat, what is a date as integer. The newest documents should get a higher score (higher ranking). This means that the higher the value in the doridat field, the higher the score should be. Only the result from searching in attachment.content and doridat should influence the score.

How can I force the scoring to integrate the field (doridat) value?

My query:

GET /attachments/_search 
{  
  "size": 2,
  "from": 0,
  "query": {
    "query_string": {
      "query": "*satz*", 
      "fields": ["attachment.content", "doname^2"],
      "rewrite": "scoring_boolean"
    }
  },
  "highlight":{
    "fields":{
      "attachment.content":{}
    }
  },
  "_source": {
    "excludes": "attachment.content"
  }
}

My mapping:

{
  "attachments" : {
    "mappings" : {
      "properties" : {
        "attachment" : {
          "properties" : {
            "author" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "content" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "content_length" : {
              "type" : "long"
            },
            "content_type" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "creator_tool" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "date" : {
              "type" : "date"
            },
            "description" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "detect_language" : {
              "type" : "boolean"
            },
            "format" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "indexed_chars" : {
              "type" : "long"
            },
            "keywords" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "language" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "metadata_date" : {
              "type" : "date"
            },
            "modified" : {
              "type" : "date"
            },
            "name" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "title" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            }
          }
        },
        "content" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "daname" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "do__nr" : {
          "type" : "integer"
        },
        "do_typ" : {
          "type" : "integer"
        },
        "doext" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "doname" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "donr" : {
          "type" : "integer"
        },
        "doridat" : {
          "type" : "integer"
        },
        "dowww" : {
          "type" : "integer"
        },
        "id" : {
          "type" : "integer"
        },
        "path" : {
          "type" : "text",
          "analyzer" : "windows_path_hierarchy_analyzer"
        }
      }
    }
  }
}