CWC Async data loading from database

function executeQuery(query) {

query = query.replace(/\s+/g, ' ').trim();

HMIRuntime.Trace(">> executeQuery " + query);

return new Promise((resolve, reject) => {

(async function () {

try {

let resultList = [];

let conn = await HMIRuntime.Database.CreateConnection(connectionstring);

HMIRuntime.Trace(".executeQuery CONN");

let response = await conn.Execute(query);

if (response !== undefined && response !== null) {

HMIRuntime.Trace(".executeQuery RESPONSE NOT NULL");

let results = response.Results;

for (let result in results) {

let rows = results[result].Rows;

for (let row in rows) {

let elementList = {};

for (let key in rows[row]) {

let value = rows[row][key];

if (typeof value == "function") value = Number(value);

elementList[key] = value;

}

resultList.push(elementList);

}

}

} else {

HMIRuntime.Trace(".executeQuery RESPONSE NULL");

}

conn.Close();

HMIRuntime.Trace(".executeQuery CONN CLOSE");

resolve(resultList);

} catch (e) {

HMIRuntime.Trace(".executeQuery ERROR");

let results = e.Results;

for (let result in results) {

let errors = results[result].Errors;

for (let i in errors) {

HMIRuntime.Trace("ERROR: " + errors[i].State + " - " + errors[i].Message);

}

}

reject();

}

})();

});

}

Where "connectionstring" is your connection string to the database

to call the function : 

function readFromDb() {

 return new Promise((resolve,reject)=>{

  let query="SELECT TOP (1) [fit] FROM [test].[dbo].[PLCDATA];";

  executeQuery(query)

   .then(

     (data)=>{

       resolve(data[0].fit);

     });

  });

}