Which is more efficient, looping through DataTable or more database calls?

[inibliozy]

Basically I have a \[code\]DataTable\[/code\] with a rows containing part numbers and a couple of columns that contain information on those parts.In order to compare those infos with the data we have in the database, I have determined I have one of two options.Option 1 - Loop through each row and SELECT the data\[code\]void CompareData(DataTable dt) { foreach (DataRow entry in dt.Rows) { //select that row DataRow dbEntry = ExecuteQuery("SELECT * FROM Parts WHERE partno='" + entry["partno"] + "'").Rows[0]; if (dbEntry["info1"] == entry["info1"]) { //do something } else { //do something } }}\[/code\]Option 2 - SELECT all data at once and compare via loops\[code\]void CompareData(DataTable dt, string[] parts) { DataTable dbEntries = ExecuteQuery("SELECT * FROM Parts WHERE partno IN('" + String.Join(parts, "','") + "')"); foreach (DataRow entry in dt.Rows) { foreach (DataRow dbEntry in dt.Rows) { if (dbEntry["partno"] == entry["partno"]) { if (dbEntry["info1"] == entry["info1"]) { //do something } else { //do something } } } }}\[/code\]They both seem pretty inefficient, so I'm not really sure what to do. Would LINQ speed this process up? I've never really used it but just browsing around it looks like something that could help.