Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
451 views
in Technique[技术] by (71.8m points)

Web SQL Database + Javascript loop

I'm trying to figure this out but can't seem to on my own...
I'm playing with Web SQL DBs and I can't get a loop to work properly with it.
I use:

for (var i=0; i<=numberofArticles-1; i++){  
    db.transaction(function (tx) {  
    tx.executeSql('INSERT INTO LOGS (articleID) VALUES (?)',  [i]);
  });
 };

And I get only 5's.. I don't get the incremental i values.
Can anyone suggestion what I'm doing wrong and what I should be thinking about?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

Do it the other way around:

<script>
    numberofArticles = 5;
    db = openDatabase("websql", "0.1", "web-sql testing", 10000);
    db.transaction(function(tx) {
        tx.executeSql('CREATE TABLE IF NOT EXISTS LOGS (id unique, articleID int)');
    });
    db.transaction(function (tx) {  
        for (var i=0; i<=numberofArticles-1; i++){  
            tx.executeSql('INSERT INTO LOGS (articleID) VALUES (?)',  [i]);
        };
    });
</script>

And the alternative, the proper way with the loop outside which is unnecessary in this case

    for (var i=0; i<=numberofArticles-1; i++){  
      (function(i) {
        db.transaction(function (tx) {  
                tx.executeSql('INSERT INTO LOGS (articleID) VALUES (?)',  [i]);
        });
      })(i);
    };

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...