QML 数据库操作 简易篇
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此博客仅作记录备忘之用
QML 数据库操作 简易篇
在自己练习写QML小应用的时候，想用db来保存音乐播放列表的信息，发现qml操作数据库还是挺方便的，虽然可能像网上说的那样会不安全。
但是只是音乐播放列表，谁关心这个呢。
现在记录下来备忘。
目前的试验结果里，在PC端还是可以正常使用的，未在别的平台上试用过。
以下函数应该算是比较简明的了。
/*添加歌曲到播放列表中*/
function add_song_to_playlist(song_url, song_name){
var song_star = 0;
console.log("add_song_to_playlist", playListName, song_url, song_name, song_star);
var db = Sql.LocalStorage.openDatabaseSync("SimpleMusicPlayerDB", "1.0", "DB for music store", 1000000);
db.transaction(
function(tx) {
tx.executeSql("CREATE TABLE IF NOT EXISTS " + playlistPopupUi.playListName + "(fileurl TEXT, songname TEXT, songstar INTEGER)" );
tx.executeSql("INSERT INTO " + playlistPopupUi.playListName + " VALUES(?, ?, ?)", [ song_url, song_name, song_star ])
}
)
playlistPopupUi.model.append({"songname":song_name, "fileurl":String(song_url)});
}
/*创建表*/
function create_table_for_playlist(table_name){
console.log("create_table_for_playlist", table_name);
var db = Sql.LocalStorage.openDatabaseSync("SimpleMusicPlayerDB", "1.0", "DB for music store", 1000000);
db.transaction(
function(tx) {
tx.executeSql("CREATE TABLE IF NOT EXISTS " + table_name + "(fileurl TEXT, songname TEXT, songstar INTEGER)" );
}
)
}
/*清空播放列表*/
function clean_playlist_info(table_name){
console.log("clean_playlist_info", table_name);
var db = Sql.LocalStorage.openDatabaseSync("SimpleMusicPlayerDB", "1.0", "DB for music store", 1000000);
db.transaction(
function(tx) {
tx.executeSql("TRUNCATE TABLE " + table_name );
}
)
playlistPopupUi.model.clear();
}
/*删除播放列表*/
function delete_playlist_from_db(table_name){
console.log("delete_playlist_from_db ", table_name);
var db = Sql.LocalStorage.openDatabaseSync("SimpleMusicPlayerDB", "1.0", "DB for music store", 1000000);
db.transaction(
function(tx) {
tx.executeSql("DROP TABLE " + table_name );
}
)
playlistPopupUi.model.clear();
}
/*重命名播放列表*/
function rename_playlist(old_table_name, new_table_name){
console.log("rename_playlist ", old_table_name, new_table_name);
var db = Sql.LocalStroage.openDatabaseSync("SimpleMusicPlayerDB", "1.0", "DB for music store", 1000000);
db.transaction(
function(tx) {
tx.executeSql("EXEC sp_rename ?, ?" , [ old_table_name, new_table_name ]);
}
)
playlistPopupUi.playListName = new_table_name;
}
/* 加载播放列表 */
function load_db_playlist(table_name){
console.log("load_db_playlist", table_name);
playlistPopupUi.model.clear();
var db = Sql.LocalStorage.openDatabaseSync("SimpleMusicPlayerDB", "1.0", "DB for music store", 1000000);
db.transaction(
function(tx) {
tx.executeSql("CREATE TABLE IF NOT EXISTS " + table_name + "(fileurl TEXT, songname TEXT, songstar INTEGER)");
var rs = tx.executeSql("SELECT * FROM "+table_name);
var r = "";
for (var i = 0; i < rs.rows.length; i++){
playlistPopupUi.model.append({"fileurl":rs.rows.item(i).fileurl ,"songname":rs.rows.item(i).songname});
}
}
)
}
/*
model: fileurl, songname, songstar
table: fileurl, songname, songstar
*/
/* 从播放列表中删除歌曲 - songname, fileurl, songstar */
function delete_song_from_playlist(song_index){
console.log("delete_song_from_playlist", song_index, playlistPopupUi.playListName, playlistPopupUi.model.get(song_index).fileurl);
var db = Sql.LocalStorage.openDatabaseSync("SimpleMusicPlayerDB", "1.0", "DB for music store", 1000000);
console.log("Sql.LocalStorage.openDatabaseSync OK")
db.transaction(
function(tx) {
tx.executeSql("DELETE FROM " + playlistPopupUi.playListName + " WHERE fileurl = " + "?", playlistPopupUi.model.get(song_index).fileurl);
}
)
playlistPopupUi.model.remove(song_index);
}
比较悲伤的是，我的小应用还没有完成。
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