引數名稱''已被宣告。引數名稱必須是唯一的

我在這里有一個在 NodeJS 中創建的 API。當我運行 API 時，它第一次運行，但如果再次運行它會給我一個錯誤The parameter name Username has already been declared. Parameter names must be unique at Request.input。我檢查了其他執行緒如何解決這個問題。一些需要清除的答案，但我認為NodeJSmssql庫中沒有清除引數的函式。（如果我錯了，請糾正我）

我的代碼：

const res = require("express/lib/response")
const {sql,request} = require("../config/connection")

module.exports = {
checkExist: (data,callBack) => {
   
    if(data.key == process.env.KEY) {

        var username = data.username
        var firstname = data.firstname
        var middlename = data.middlename
        var lastname = data.lastname

        if(username == "" || firstname == "" || middlename == "" || lastname == "") {
            return callBack("Invalid Input")
        }
        else {
            request.input('Username', sql.VarChar(50), username);
            request.input('FirstName', sql.VarChar(50), firstname);
            request.input('MiddleName', sql.VarChar(50), middlename);
            request.input('LastName', sql.VarChar(50), lastname);
            request.output('Result', sql.Int);

            request.execute('sp_INS_User').then(function(recordsets, returnValue, affected) {
                if(recordsets.output.Result == -100) {
                    return callBack("Player Exist with different Username")
                }
                else if(recordsets.output.Result == -4) {
                    return callBack("Something went wrong while processing your request, please try again later.")
                }
                else {
                    if(recordsets.output.Result == 1000) {
                        return callBack(null,recordsets)
                    }
                }
               
                // console.dir(err);
              }).catch(function(err) {
                //return callBack(err)
                return callBack("Something went wrong while processing your request, please try again later.")
           });
        }
       

    }
    else {
            return callBack("Invalid Access")
    }
}

}

我的代碼：../config/connection/

const sql = require("mssql")
require("dotenv").config()

const sqlConfig = {
user: process.env.USER,
password: process.env.PASS,
database: process.env.DB_MAIN,
server: process.env.HOST,
pool: {
    max: 10,
    min: 0,
    idleTimeoutMillis: 30000
},
options: {
    encrypt:false,
    trustServerCertificate: true
}

}

const con = sql.connect(sqlConfig).then(function() {

console.log(`Database connection successful!`);

}).catch(function(err) {
console.log(`Database connection ${err}!`);

});

const request = new sql.Request();

module.exports = {
sql,request
}

uj5u.com熱心網友回復：

這看起來像是重用請求物件的問題，因此第二次呼叫此函式時，您使用的請求物件與之前第一次呼叫此函式時使用的請求物件相同。因此，您正在使用 注冊重復名稱request.input()。

const request = new sql.Request();顯然，每次要使用它時都需要一個新副本，因為錯誤訊息告訴您不能 request.input('Username',...)在同一個請求物件上一遍又一遍地重復陳述句。因此，匯出一個函式來獲取一個新request物件，而不是只匯出一個預制物件。

你可以這樣做：

../配置/連接/

const sql = require("mssql")
require("dotenv").config()

const sqlConfig = {
user: process.env.USER,
password: process.env.PASS,
database: process.env.DB_MAIN,
server: process.env.HOST,
pool: {
    max: 10,
    min: 0,
    idleTimeoutMillis: 30000
},
options: {
    encrypt:false,
    trustServerCertificate: true
}

}

const con = sql.connect(sqlConfig).then(function() {

console.log(`Database connection successful!`);

}).catch(function(err) {
console.log(`Database connection ${err}!`);

});

const getRequest = function() { return new sql.Request(); };

module.exports = {
    sql, getRequest
};

而且，您的其他代碼：

const res = require("express/lib/response")
const { sql, getRequest } = require("../config/connection")

module.exports = {
    checkExist: (data, callBack) => {

        const request = getRequest();

        if (data.key == process.env.CAMS_INPLAY_KEY) {

            var username = data.username
            var firstname = data.firstname
            var middlename = data.middlename
            var lastname = data.lastname

            if (username == "" || firstname == "" || middlename == "" || lastname == "") {
                return callBack("Invalid Input")
            } else {
                request.input('Username', sql.VarChar(50), username);
                request.input('FirstName', sql.VarChar(50), firstname);
                request.input('MiddleName', sql.VarChar(50), middlename);
                request.input('LastName', sql.VarChar(50), lastname);
                request.output('Result', sql.Int);

                request.execute('sp_INS_User').then(function(recordsets, returnValue, affected) {
                    if (recordsets.output.Result == -100) {
                        return callBack("Player Exist with different Username")
                    } else if (recordsets.output.Result == -4) {
                        return callBack(
                            "Something went wrong while processing your request, please try again later."
                            )
                    } else {
                        if (recordsets.output.Result == 1000) {
                            return callBack(null, recordsets)
                        }
                    }

                    // console.dir(err);
                }).catch(function(err) {
                    //return callBack(err)
                    return callBack(
                        "Something went wrong while processing your request, please try again later."
                        )
                });
            }


        } else {
            return callBack("Invalid Access")
        }
    }

}

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