如何读取用 Node.js 查询的 Oracle 数据库 XML 列？

Question

I need to read the value that will bring my query to the database in Oracle, I use oracle DB and node.js. the oracle DB returns these values in the column that has XML, but the other columns that has normal values return ok.

{
  "tramaenv": {
    "_readableState": {
      "objectMode": false,
      "highWaterMark": 16384,
      "buffer": {
        "head": null,
        "tail": null,
        "length": 0
      },
      "length": 0,
      "pipes": null,
      "pipesCount": 0,
      "flowing": null,
      "ended": false,
      "endEmitted": false,
      "reading": false,
      "sync": true,
      "needReadable": false,
      "emittedReadable": false,
      "readableListening": false,
      "resumeScheduled": false,
      "emitClose": true,
      "autoDestroy": false,
      "destroyed": false,
      "defaultEncoding": "utf8",
      "awaitDrain": 0,
      "readingMore": false,
      "decoder": null,
      "encoding": null
    },
    "readable": true,
    "_events": {},
    "_eventsCount": 1,
    "_writableState": {
      "corkedRequestsFree": {
        "next": null,
        "entry": null
      }
    },
    "writable": true,
    "allowHalfOpen": true,
    "offset": 1
  }
}

but the real content is this XML

<soapenv:Envelope >
    <soapenv:Header/>
    <soapenv:Body>
        <imp:obtNroConstanciaElectronica>
            <reqObtNroConstanciaElectronica>
                <idecotizacion>12668264</idecotizacion>
                <ideprod>2003</ideprod>
            </reqObtNroConstanciaElectronica>
        </imp:obtNroConstanciaElectronica>
    </soapenv:Body>
</soapenv:Envelope>

Answer 1

If your sample data is:

CREATE TABLE table_name ( id, xml ) AS
SELECT 1, '<soapenv:Envelope xmlns:soapenv="https://example.com/soapenv" xmlns:imp="https://example.com/imp">
    <soapenv:Header/>
    <soapenv:Body>
        <imp:obtNroConstanciaElectronica>
            <reqObtNroConstanciaElectronica>
                <idecotizacion>12668264</idecotizacion>
                <ideprod>2003</ideprod>
            </reqObtNroConstanciaElectronica>
        </imp:obtNroConstanciaElectronica>
    </soapenv:Body>
</soapenv:Envelope>' FROM DUAL;

(Note: that the namespaces for soapenv and imp are declared in the XML.)

Then you can use the SQL query:

SELECT id,
       x.*
FROM   table_name t
       CROSS APPLY XMLTABLE(
         XMLNAMESPACES(
           'https://example.com/soapenv' AS "soapenv",
           'https://example.com/imp' AS "imp"
         ),
         '/soapenv:Envelope/soapenv:Body/imp:obtNroConstanciaElectronica/reqObtNroConstanciaElectronica'
         PASSING XMLTYPE( t.xml )
         COLUMNS
           idecotizacion NUMBER PATH './idecotizacion',
           ideprod NUMBER PATH './ideprod'
       ) x

And the output is:

ID	IDECOTIZACION	IDEPROD
1	12668264	2003

Then you just need to call that query as you would any other SQL query in your node.js script and get the values.

Answer 2

The node-oracledb documentation has a whole section on XMLType .

It appears that you have successfully fetched as CLOB (which is necessary to avoid the XML length being limited to the maxium VARCHAR2 length), ie. you've done something like:

const sql = `SELECT XMLTYPE.GETCLOBVAL(res) FROM resource_view`;

You can either stream the LOB , or tell node-oracledb to return it directly as a string . To do the latter, add this to the top of your script:

oracledb.fetchAsString = [ oracledb.CLOB ];

You should benchmark both solutions and use what's best.