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POBest method to string together variety of DB calls in Node js
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copied!<p>I basically need to make about 3 calls to get the data for a json object.. It basically JSON array of JSON object which have some attributes, one of which is an array of other values selected using a second query, then that one also has an array inside which is selected with another db call.</p> <p>I tried using asyn.concatSeries so that I can dig down into the bottom call and put together all the information I collected for one root json object but that's creating a lot of unexpected behaviour..</p> <p>Example of JSON</p> <pre><code>[ { "item" : "firstDbCall" "children" : [ { "name" : "itemDiscoveredWithSecondDBCall" "children" : [ itemsDiscoveredwith3rdDBCall] }, ] } ] </code></pre> <p>This is really difficult using node.js. I really need to figure out how to do this properly since I have to do many of these for different purposes.</p> <p><strong>EDIT</strong> This is the code i have. There's some strange behaviour with async.concatSeries. The results get called multiple times after each one of the functions finish for each array. So i had to put a check in place. I know it's very messy code but i've been just putting band-aids all over it for the past 2 hours to make it work.. </p> <pre><code>console.log("GET USERS HAREDQARE INFO _--__--_-_-_-_-_____"); var query = "select driveGroupId from tasks, driveInformation where agentId = '" + req.params.agentId + "' and driveInformation.taskId = tasks.id order by driveInformation.taskId desc;"; connection.query(query, function(err, rows) { if (rows === undefined) { res.json([]); return; } if(rows.length<1) { res.send("[]"); return;} var driveGroupId = rows[0].driveGroupId; var physicalQuery = "select * from drives where driveGroupId = " + driveGroupId + ";"; connection.query(physicalQuery, function(err, rows) { console.log("ROWSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS"); console.log(rows); async.concatSeries(rows, function(row, cb) { console.log("-------------------------------SINGLE ROW-------------------------------------"); console.log(row); if(row.hasLogicalDrives != 0) { console.log("HAS LOGICAL DRIVES"); console.log(row.id); var query = "select id, name from logicalDrives where driveId = " + row.id; connection.query(query, function(error, drives) { console.log("QUERY RETURNED"); console.log(drives); parseDriveInfo(row.name, row.searchable, drives, cb); }); } else var driveInfo = { "driveName" : row.name, "searchable" : row.searchable}; console.log("NO SUB ITEMS"); cb(null, driveInfo); }, function(err, results) { console.log("GEETTTTINGHERE"); console.log(results); if(results.length == rows.length) { console.log("RESULTS FOR THE DRIVE SEARCH"); console.log(results); var response = {"id": req.params.agentId}; response.driveList = results; console.log("RESPONSE"); console.log(response); res.json(response); } }); }); }); }; parseDriveInfo = function(driveName, searchable, drives, cb) { async.concatSeries(drives, function(drive,callback) { console.log("SERIES 2"); console.log(drive); console.log("END OF DRIVE INFO"); var query = "select name from supportedSearchTypes where logicalDriveId = " + drive.id; connection.query(query, function(error, searchTypes) { drive.searchTypes = searchTypes; var driveInfo = { "driveName" :driveName, "searchable" : searchable, "logicalDrives" : drive }; callback(null, driveInfo); }); }, function (err, results) { console.log("THIS IS ISISIS ISISISSISISISISISISISISISIS"); console.log(results); if(results.length === drives.length) { console.log("GOTHERE"); cb(null, results); } }); </code></pre> <p>}</p>

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