PhoneGap的SQL检查重复

Question

我想输入一个查询将数据插入到数据库时检查重复的数据库，以便它可能会妨碍活动名称被多次输入一个数据库

function insertQueryDB(tx) { 
    var myDB = window.openDatabase("test", "1.0", "Test DB", 1000000); 
    tx.executeSql('CREATE TABLE IF NOT EXISTS dataEntryTb (id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, activityName TEXT NOT NULL, location TEXT NOT NULL, time NOT NULL, date NOT NULL, reporter NOT NULL)'); 
     var an = document.forms["myForm"]["activityName"].value; 
     var l = document.forms["myForm"]["location"].value; 
     var t = document.forms["myForm"]["time"].value; 
     var d = document.forms["myForm"]["date"].value; 
     var r = document.forms["myForm"]["reporter"].value; 
     var query = 'INSERT INTO dataEntryTb (activityName, location, time, date, reporter) VALUES ("'+an+'", "'+l+'", "'+t+'", "'+d+'", "'+r+'")'; 

     navigator.notification.alert("Retrieved the following: Activity Name="+an+" and Location="+l); 
     tx.executeSql(query,[]); 
    }`` 

Answer 1

创建与名称为unique表：

CREATE TABLE IF NOT EXISTS dataEntryTb (
    id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, 
    activityName TEXT NOT NULL UNIQUE, 
    location TEXT NOT NULL, 
    time NOT NULL, date NOT NULL, 
    reporter NOT NULL 
); 

这时如果名称已在该表的数据库会返回一个错误。