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[英]Does iOS Sqlite database get locked in simultaneous background and foreground operation?
[英]iOS Phonegap sqlite database getting locked when app go to background
現在,我正在開發一個phonegap應用程序:
當app進入iOS后台時,sqlite db中的插入操作被鎖定(在android中也是如此)。 當應用程序處於前台時,數據庫操作將順利進行。
為什么會這樣,我該如何處理?
我認為您已經使用了插入循環,而Javascript本質上是異步的。
您需要以以下樣式執行批處理sql查詢,而不是使用for循環
db = window.openDatabase(“ Demo”,“ 1.0”,“ BusinessApp”,200000);
insertIndex = 0;
var insertCounter = 0;
insertBatch = function(array, arrayLength, tableName, fieldQuestions, cb) {
console.log("Inserting Record :" + insertCounter);
if (insertIndex < arrayLength) {
db.transaction(function(tx) {
var sql = 'INSERT OR IGNORE INTO ' + tableName + ' VALUES ' + fieldQuestions;
console.log("sql: " + sql);
console.log("sql:------------- ");
console.log(array[insertIndex]);
tx.executeSql(sql, array[insertIndex],
function(tx, res) {
insertIndex++;
console.log("Insert success");
insertBatch(array, arrayLength, tableName, fieldQuestions, cb);
}, function() {
console.log("Insert failure");
});
});
} else {
insertIndex = 0;
cb();
}
}
db.transaction(populateDB, errorCB, successCB);
function populateDB(tx) {
tx.executeSql('DROP TABLE IF EXISTS ?', ["news"], function() {
console.log("success drop")
}, function() {
console.log("failure drop")
});
tx.executeSql('CREATE TABLE IF NOT EXISTS news (news_id INTEGER,news_header TEXT,news_content TEXT)');
}
function errorCB() {
alert("Error: Init.js ErrorCB");
}
function successCB() {
//alert();
console.log('DB Created Success');
var dataArray = []
dataArray.push([1, "ONE", "First News Content"])
dataArray.push([2, "TWO", "2 News Content"])
dataArray.push([3, "THREE", "2 News Content"])
dataArray.push([4, "FOUR", "4 News Content"])
insertBatch(dataArray, dataArray.length, "news", "(?,?,?)", success)
function success() {
console.log("all success")
}
}
因此,每個executeSQ L函數都需要先前的executeSQL成功回調
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