PhoneGap存储，将变量传递给db.transaction，SQL Lite

Question

I'm working with the PhoneGap Open Database API. According to this documentation values should be inserted into an existing table using the follow code

function populateDB(tx) {
     tx.executeSql('DROP TABLE IF EXISTS DEMO');
     tx.executeSql('CREATE TABLE IF NOT EXISTS DEMO (id unique, data)');
     tx.executeSql('INSERT INTO DEMO (id, data) VALUES (1, "First row")');
     tx.executeSql('INSERT INTO DEMO (id, data) VALUES (2, "Second row")');
}

function errorCB(tx, err) {
    alert("Error processing SQL: "+err);
}

function successCB() {
    alert("success!");
}

  var db = window.openDatabase("Database", "1.0", "PhoneGap Demo", 200000);
  db.transaction(populateDB, errorCB, successCB);

This works fine but now I'm trying to pass a variable to the populateDB function. When I try the code below

  var db = window.openDatabase("Database", "1.0", "PhoneGap Demo", 200000);
  db.transaction(populateDB("test variable"), errorCB, successCB);

the "test variable" string goes through but tx is undefined. Does anyone know how to do this?

Answer 1

I think the only way you could do this would be write a function that returns a function that makes use of the passed in value. Something along the lines of :

function makeMyDB(x) {
    var result = function() {
     tx.executeSql('DROP TABLE IF EXISTS DEMO');
     tx.executeSql('CREATE TABLE IF NOT EXISTS DEMO (id unique, data)');
     tx.executeSql('INSERT INTO DEMO (id, data) VALUES (1, "'+x+'")');
    }
   return result;
} 

You could then try passing makeMyDB(x) as the first argument.

Answer 2

If anyone else is still looking for a solution to this problem, I have a little solution for passing variable without changing or loosing the tx , you just have to write this for example:

var myvar = 1; //an int or something else
db.transaction(function(tx){
    selectQueryDB(tx,myvar);
    },errorCB);



function selectQueryDB(tx,myvar){
    tx.executeSql('SELECT * FROM mytable WHERE myparam='+myvar, [], renderList, errorCB);

}

function errorCB(err){
    alert("Error Processing SQL: "+ err.code );
}
function renderList(tx,results){
enter code here
}