Unable to form correct JQ to get proper output from JSON data

I am using JQ Play.

Here is my JSON Data -

{"body": {"name": "DATATYPES","primarykey": ["db_number"],"members": [  {"name": "db_number","type": "NUMBER"  },  {"name": "db_date","type": "DATE"  },  {"name": "db_timestamp","type": "TIMESTAMP(6)"  },  {"name": "db_timestamp_with_local_time_zone","type": "TIMESTAMP(6) WITH LOCAL TIME ZONE"  },  {"name": "db_char","type": "CHAR"  },  {"name": "db_float","type": "FLOAT"  },  {"name": "db_nchar","type": "NCHAR"  },  {"name": "db_nvarchar2","type": "NVARCHAR2"  },  {"name": "db_varchar2","type": "VARCHAR2"  },  {"name": "db_binary_float","type": "BINARY_FLOAT"  },  {"name": "db_binary_double","type": "BINARY_DOUBLE"  },  {"name": "db_timestamp_with_time_zone","type": "TIMESTAMP(6) WITH TIME ZONE"  },  {"name": "db_interval_year_to_month","type": "INTERVAL YEAR(2) TO MONTH"  },  {"name": "db_interval_day_to_second","type": "INTERVAL DAY(2) TO SECOND(6)"  },  {"name": "db_long","type": "LONG"  },  {"name": "db_blob","type": "BLOB"  },  {"name": "db_clob","type": "CLOB"  },  {"name": "db_boolean","type": "CHAR"  }  ],"links": [  {"rel": "collection","href": "https://tdcvm28s16.bcone.com:7002/ords/testords/metadata-catalog/","mediaType": "application/json"  },  {"rel": "canonical","href": "https://tdcvm28s16.bcone.com:7002/ords/testords/metadata-catalog/datatypes/","mediaType": "application/json"  },  {"rel": "alternate","href": "https://tdcvm28s16.bcone.com:7002/ords/testords/open-api-catalog/datatypes/","mediaType": "application/openapi+json"  },  {"rel": "describes","href": "https://tdcvm28s16.bcone.com:7002/ords/testords/datatypes/"  }  ]  }  }

My First JQ -

{"parameters":([.body.primarykey[0]] | reduce .[] as $item ({}; .[$item] = ""))}

Output -

{"parameters": {"db_number": ""}}

Here, my requirement is - I want type of primary also in parameters in output by comparing it with matching record from members.

My expected output is -

{"parameters": {"db_number": "number"}}

Please help me with correct JQ that will work in jqplay.org

My Second JQ -

.body.primarykey[] as $k | {  parameters: {($k): "" }, body: (.body.members | map( select(.name != $k) | {(.name): .type |ascii_downcase}) | add)}

Here, my requirement is - I want same parameters as above with type of primarykey along with body which eliminates matching primarykey from body.

My expected output is -

{"parameters": {"db_number": "number"},"body": {"db_date": "date","db_timestamp": "timestamp(6)","db_timestamp_with_local_time_zone": "timestamp(6) with local time zone","db_char": "char","db_float": "float","db_nchar": "nchar","db_nvarchar2": "nvarchar2","db_varchar2": "varchar2","db_binary_float": "binary_float","db_binary_double": "binary_double","db_timestamp_with_time_zone": "timestamp(6) with time zone","db_interval_year_to_month": "interval year(2) to month","db_interval_day_to_second": "interval day(2) to second(6)","db_long": "long","db_blob": "blob","db_clob": "clob","db_boolean": "char"}}

Please help me with correct JQ that will work in jqplay.org