本文整理汇总了C#中SQLite.SQLiteConnection.ExecuteScalar方法的典型用法代码示例。如果您正苦于以下问题：C# SQLiteConnection.ExecuteScalar方法的具体用法？C# SQLiteConnection.ExecuteScalar怎么用？C# SQLiteConnection.ExecuteScalar使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类SQLite.SQLiteConnection的用法示例。
在下文中一共展示了SQLiteConnection.ExecuteScalar方法的15个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C#代码示例。
示例1: App
public App()
{
// The root page of your application
MainPage = new ContentPage {
Content = new StackLayout {
VerticalOptions = LayoutOptions.Center,
Children = {
new Label {
XAlign = TextAlignment.Center,
Text = "Welcome to Xamarin Forms!"
}
}
}
};
// path to db
var path = Path.Combine (Environment.GetFolderPath (Environment.SpecialFolder.MyDocuments), "mydb");
// open connection and attempt to apply encryption using PRAGMA statement
var conn = new SQLiteConnection (path);
conn.Execute ("PRAGMA key = 'passme'");
int v = conn.ExecuteScalar<int> ("SELECT count(*) FROM sqlite_master");
conn.Close ();
// open another connection, this time use wrong password. It will still open, but should fail the
// query (see docs on key PRAGMA https://www.zetetic.net/sqlcipher/sqlcipher-api/)
var conn2 = new SQLiteConnection (path);
conn2.Execute ("PRAGMA key = 'wrongpassword'");
int v2 = conn2.ExecuteScalar<int> ("SELECT count(*) FROM sqlite_master");
conn2.Close ();
}示例2: FootballPlayer
public FootballPlayer()
{
database = DependencyService.Get<MySqlConn> ().getConnection ();
var count = database.ExecuteScalar<int> ("SELECT Count(*) FROM FootballPlayer");
if (count == 0) {
database.CreateTable<FootballPlayer> ();
}
}示例3: isTableExisting
private static bool isTableExisting(string strTblName){
try{
var connection = new SQLiteConnection(path);
var count = connection.ExecuteScalar<int>("SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='" + strTblName + "'");
if(count > 0){
return true;
}else{
return false;
}
}catch(SQLiteException){
return false;
}
}示例4: MapServiceSQLite
public MapServiceSQLite()
{
using (SQLiteConnection connection = new SQLiteConnection(SQLiteConfiguration.ConnectionString))
{
connection.CreateTable<MapModel>();
if (connection.ExecuteScalar<int>("SELECT COUNT(*) FROM Maps") == 0)
connection.RunInTransaction(() =>
{
connection.Insert(new MapModel(Guid.NewGuid(), "Default Map", @"ms-appx:///MetroExplorer.Components.Maps/DesignAssets/MapBackground.bmp"));
});
connection.CreateTable<MapLocationModel>();
connection.CreateTable<MapLocationFolderModel>();
}
}示例5: clickFoodDialogList
private void clickFoodDialogList(object sender, DialogClickEventArgs args)
{
listChoice = choices [args.Which];
Console.WriteLine ("Selected: {0}", args.Which);
// Open a confirmation alert
AlertDialog.Builder confirmFoodDialogBuilder = new AlertDialog.Builder(this);
confirmFoodDialogBuilder.SetTitle ("Confirm selection");
confirmFoodDialogBuilder.SetMessage ("You are adding the following choice: " +
listChoice + ". Do you wish to proceed?");
// Insert the selection into the database on confirmation
confirmFoodDialogBuilder.SetPositiveButton ("Confirm", delegate {
dismissAddFoodDialog ();
LogEntry newLog = new LogEntry {
LoggedAt = DateTime.Now,
Level = LogEntry.MapToLevel(args.Which)
};
using (var db = new SQLiteConnection(dbPath)) {
db.Insert (newLog);
var count = db.ExecuteScalar<int> ("Select COUNT(*) from LogEntry");
Console.WriteLine("There are now {0} Log Entries", count);
}
});
// Close all alerts if the user cancels at this point
confirmFoodDialogBuilder.SetNegativeButton ("Cancel", delegate {
dismissAddFoodDialog ();
});
confirmFoodDialog = confirmFoodDialogBuilder.Create ();
confirmFoodDialog.Show ();
}示例6: OnCreate
//.........这里部分代码省略.........
{
try
{
var sql = "delete from PERSON";
int oldDataCount = conn.Execute(sql);
new AlertDialog.Builder(this).SetMessage(string.Format("旧数据有{0}条", oldDataCount)).Show();
sql = "DROP TABLE [PERSON];";
conn.Execute(sql);
sql = @"CREATE TABLE [PERSON] (
[ID] nvarchar(2147483647) NOT NULL
, [NAME] nvarchar(2147483647) NULL
, [DEPARTMENT] nvarchar(2147483647) NULL
, [MOBILE_PHONE] nvarchar(2147483647) NULL
, [VIRTUAL_PHONE] nvarchar(2147483647) NULL
, [POSITION] nvarchar(2147483647) NULL
, [REGION] nvarchar(2147483647) NULL
, [OFFICE_PHONE] nvarchar(2147483647) NULL
, [INNER_PHONE] nvarchar(2147483647) NULL
, [PY] nvarchar(2147483647) NULL
, [CAR] nvarchar(2147483647) NULL
, CONSTRAINT [sqlite_autoindex_PERSON_1] PRIMARY KEY ([ID])
);";
conn.Execute(sql);
conn.BeginTransaction();
conn.InsertAll(personList);
textViewCurrentVersion.Text = textViewLatestVersion.Text;
editor.PutString("version", textViewCurrentVersion.Text);
editor.Commit();
sql = "select count(ID) from PERSON";
int newDataCount = conn.ExecuteScalar<int>(sql);
new AlertDialog.Builder(this).SetMessage(string.Format("新数据有{0}条", newDataCount)).Show();
conn.Commit();
new AlertDialog.Builder(this).SetMessage("更新完毕").SetPositiveButton("确定", delegate
{
}).Show();
}
catch (Exception ex)
{
conn.Rollback();
new AlertDialog.Builder(this).SetMessage(ex.Message).Show();
}
}
}
}
}
}
else
{
new AlertDialog.Builder(this).SetMessage("无需更新").Show();
}
}
catch (System.Exception ex)
{
new AlertDialog.Builder(this).SetMessage(ex.Message).Show();
}
finally
{示例7: ScalarQuery
public static string ScalarQuery ()
{
var output = "";
output += "\nScalar query example: ";
string dbPath = Path.Combine (
Environment.GetFolderPath (Environment.SpecialFolder.Personal), "ormdemo.db3");
var db = new SQLiteConnection (dbPath);
var rowcount = db.ExecuteScalar<int> ("SELECT COUNT(*) FROM [Items] WHERE Symbol <> ?", "MSFT");
output += "\nNumber of rows : " + rowcount;
return output;
}示例8: getCurrentSig
private static string getCurrentSig(SQLiteConnection db)
{
string json = db.ExecuteScalar<string>("SELECT v FROM t$v WHERE k=10");
return DependencyService.Get<ISHA1Service>().HashString(json);
}示例9: open_and_load_zumero
private static SQLiteConnection open_and_load_zumero(string s)
{
// open the local SQLite db
SQLiteConnection db = new SQLiteConnection(s);
// tell SQLite to allow load_extension()
db.EnableLoadExtension(1);
// load the Zumero extension
// this is the equivalent of ".load zumero.dylib" in the sqlite3 shell
db.ExecuteScalar<string>("SELECT load_extension('zumero.dylib');");
return db;
}示例10: do_feeds
private static void do_feeds(SQLiteConnection db, List<feed_row> rows)
{
foreach (feed_row q in rows)
{
string dbfile_name_for_this_feed = string.Format("feed_{0}", q.feedid);
Console.WriteLine("Updating {0}: {1}", dbfile_name_for_this_feed, q.url);
SyndicationFeed f = null;
try
{
XmlReader xr = new XmlTextReader(q.url);
f = SyndicationFeed.Load(xr);
}
catch (Exception e)
{
Console.WriteLine("{0}", e);
// TODO failed trying to retrieve or parse this feed.
// TODO log the failure?
// TODO delete the feed row?
// TODO launch nethack?
}
if (f != null)
{
db.Execute("ATTACH ? AS cur;", dbfile_name_for_this_feed);
bool found = false;
var query = "pragma cur.table_info(\"items\")";
List<SQLiteConnection.ColumnInfo> cols = db.Query<SQLiteConnection.ColumnInfo> (query);
foreach (var c in cols) {
found = (string.Compare ("permalink", c.Name, StringComparison.OrdinalIgnoreCase) == 0);
if (found)
break;
}
if (! found)
{
db.Execute("BEGIN TRANSACTION;");
db.ExecuteScalar<string>(@"select zumero_alter_table_add_column('cur', 'items', 'permalink TEXT');");
db.Execute("COMMIT TRANSACTION;");
// after altering a zumero table, the dbfile connection must be reopened
db.Execute("DETACH cur;", dbfile_name_for_this_feed);
db.Execute("ATTACH ? AS cur;", dbfile_name_for_this_feed);
}
db.Execute("BEGIN TRANSACTION;");
// set last_update to the time we retrieved the feed XML
db.Execute(
@"INSERT OR REPLACE
INTO main.last_update
(feedid, when_unix_time)
VALUES
(?, strftime('%s','now')
);",
q.feedid);
foreach (SyndicationItem it in f.Items)
{
Console.WriteLine(" {0}", it.Title.Text);
TextSyndicationContent t = (TextSyndicationContent) it.Summary;
if (null == t)
t = (TextSyndicationContent)it.Content;
string id = it.Id;
string url = null;
foreach(SyndicationLink link in it.Links)
{
url = link.Uri.ToString();
break;
}
if (null == id)
id = url;
if (null == url)
url = id;
if (null == id)
{
Console.WriteLine(" no id");
}
else
{
db.Execute("INSERT OR IGNORE INTO cur.items (id, title, summary, pubdate_unix_time, permalink) VALUES (?,?,?,?,?)",
id,
it.Title.Text,
t.Text,
(it.PublishDate.UtcDateTime - new DateTime(1970,1,1)).TotalSeconds,
url
);
}
//.........这里部分代码省略.........
示例11: do_feeds
private static void do_feeds(SQLiteConnection db, List<feed_row> rows)
{
foreach (feed_row q in rows)
{
string dbfile_name_for_this_feed = string.Format("feed_{0}", q.feedid);
Console.WriteLine("Creating {0}: {1}", dbfile_name_for_this_feed, q.url);
SyndicationFeed f = null;
try
{
XmlReader xr = new XmlTextReader(q.url);
f = SyndicationFeed.Load(xr);
}
catch (Exception e)
{
Console.WriteLine("{0}", e);
// TODO failed trying to retrieve or parse this feed.
// TODO log the failure?
// TODO delete the feed row?
// TODO launch nethack?
}
if (f != null)
{
db.Execute("ATTACH ? AS cur;", dbfile_name_for_this_feed);
db.Execute("BEGIN TRANSACTION;");
db.Execute(
@"CREATE VIRTUAL TABLE
cur.items
USING zumero
(
id TEXT PRIMARY KEY NOT NULL,
title TEXT NOT NULL,
summary TEXT NOT NULL,
pubdate_unix_time INTEGER NOT NULL,
permalink TEXT
);"
);
// each feed is allowed to be pulled by anyone, but only the admin user
// can make changes
db.ExecuteScalar<string>(
@"SELECT zumero_define_acl_table('cur');"
);
db.Execute(
@"INSERT INTO cur.z_acl
(scheme,who,tbl,op,result)
VALUES (
'',
zumero_named_constant('acl_who_anyone'),
'',
'*',
zumero_named_constant('acl_result_deny')
);"
);
db.Execute(
@"INSERT INTO cur.z_acl
(scheme,who,tbl,op,result)
VALUES (
zumero_internal_auth_scheme('zumero_users_admin'),
zumero_named_constant('acl_who_any_authenticated_user'),
'',
'*',
zumero_named_constant('acl_result_allow')
);"
);
db.Execute(
@"INSERT INTO cur.z_acl
(scheme,who,tbl,op,result)
VALUES (
'',
zumero_named_constant('acl_who_anyone'),
'',
zumero_named_constant('acl_op_pull'),
zumero_named_constant('acl_result_allow')
);"
);
// set the feed title
db.Execute("INSERT INTO main.about (feedid, title) VALUES (?,?)",
q.feedid,
f.Title.Text
);
db.Execute("COMMIT TRANSACTION;");
db.Execute("DETACH cur;");
}
}
}示例12: getCoins
public static int getCoins(){
try
{
var db = new SQLiteConnection(path);
return db.ExecuteScalar<int>("SELECT CoinsCount FROM Coins WHERE ID = 1");
}
catch (SQLiteException)
{
return 0;
}
}示例13: getRandomTip
public static string getRandomTip(){
try
{
var db = new SQLiteConnection(path);
string tip = db.ExecuteScalar<string>("SELECT TipPhrase FROM Tip WHERE ID = " + Convert.ToString(new System.Random().Next(12) + 1));
if(string.IsNullOrEmpty(tip)){
tip = "0 returned";
}
return tip;
}
catch (SQLiteException ex)
{
return ex.Message ;
}
}示例14: get_total_records
//------------------------------------------------------------------------//
//used for debugging purposes
public int get_total_records()
{
try
{
var db = new SQLiteConnection(m_db_path);
// this counts all records in the database, it can be slow depending on the size of the database
var count = db.ExecuteScalar<int>("SELECT Count(*) FROM ShopItem");
return count;
}
catch (SQLiteException ex)
{
Console.WriteLine("get total records has failed, ex.msg :{0}",ex.Message);
return -1;
}
}示例15: FetchStatsFromDate
double FetchStatsFromDate (SQLiteConnection connection, DateTime dt)
{
return connection.ExecuteScalar<double> (SumQuery, dt.ToUniversalTime ());
}