I am using SQLite for Windows Phone 7 (http://sqlitewindowsphone.codeplex.com/) and I have done every steps from this tutorial (http://dotnetslackers.com/articles/silverlight/Windows-Phone-7-Native-Database-Programming-via-Sqlite-Client-for-Windows-Phone.aspx)
Then I try to make some simple application with basic features like select and delete. App is working properly till I want to make one of this operations. After I click select or delete, compiler shows me errors that he is unable to open database file...
I have no idea why?
I used the same Sqlite client, and had the same problem. This problem occurs because the sqlite try to create file in IsolatedFileStorage "DatabaseName.sqlite-journal" and it does not have enough permissions for that. I solved the problem, so that created "DatabaseName.sqlite-journal" before copying database to IsolatedFileStorage. Here's my method that did it:
private void CopyFromContentToStorage(String assemblyName, String dbName)
{
IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication();
string uri = dbName + "-journal";
store.CreateFile(uri);
using (Stream input = Application.GetResourceStream(new Uri("/" + assemblyName + ";component/" + dbName,UriKind.Relative)).Stream)
{
IsolatedStorageFileStream dest = new IsolatedStorageFileStream(dbName, FileMode.OpenOrCreate, FileAccess.Write, store);
input.Position = 0;
CopyStream(input, dest);
dest.Flush();
dest.Close();
dest.Dispose();
}
}
it helped me, and worked well.
hope this will help you
Are you sure the file exists?
You can check like that:
using (var store = IsolatedStorageFile.GetUserStoreForApplication())
{
exists = store.FileExists(DbfileName);
}
Related
I use FluentMigrator to create a SqlLite DB in C# using FluentMigrator.Runner.MigrationRunner. I wonder is there any way to use the SetPassword command o the SqlConnection only when the DB needs to be created ? There's a SqLiteRunnerContextFactory object but it don't seem to be a property that I can use to specify password.
public MigrationRunner CreateMigrationRunner(string connectionString, string[] migrationTargets, Assembly assembly, long version)
{
var announcer = new TextWriterAnnouncer(Console.WriteLine) { ShowSql = true };
var options = new ProcessorOptions { PreviewOnly = false, Timeout = 60 };
var runnerContext = new SqLiteRunnerContextFactory().CreateRunnerContext(connectionString, migrationTargets, version, announcer);
var sqlLiteConnection = new SQLiteConnection(connectionString);
//If the DB has already been created, it crashes later on if I specify this
sqlLiteConnection.SetPassword("ban4an4");
return new MigrationRunner(assembly,
runnerContext,
new SQLiteProcessor(sqlLiteConnection,
new SQLiteGenerator(),
announcer,
options,
new SQLiteDbFactory()));
}
I would like to avoid having to look if the file exists before setting password on connection.
Well, finally the code below works perfectly by using SetPassword everytime you create de runner. No need to check if the file exists or not. First time it creates it with the password and second time it opens it with it seems to use it to open DB. Which is exactly what I was looking for.
Good day to everyone,
I'm building an application in Xamarin.Forms Portable for iOS,Android,Windows Universal(10) .
I'm trying to use the Mono.Data.Sqlite.Portable, but I'm not able to create or connect to a local database, I've tried many solutions to fix the problem, but until now I dint find the solution..
The error is trow at "connection.open();"
The Code is :
var config = DependencyService.Get<DB.IConfig>();
var cnn = config.DirectoryDB;
using (var connection = new SqliteConnection("" +
new SqliteConnectionStringBuilder
{
DataSource = "URI=file::memory:",
Version=3,
}))
{
//connection.ChangeDatabase("hello.db");
connection.Open();
using (var transaction = connection.BeginTransaction())
{
var insertCommand = connection.CreateCommand();
insertCommand.Transaction = transaction;
insertCommand.CommandText = "CREATE TABLE TESTE(teste as varchar(10))";
insertCommand.ExecuteNonQuery();
transaction.Commit();
}
}
on the "DataSource" I've a local path, and other paths.
(Ex:. C:\Users\MyMachineName\AppData\Local\Packages\f736c883-f105-4d30-a719-4bf328872f5e_nh7s0b45jarrj\LocalState\hello.db)
The error is :
An exception of type 'System.NotImplementedException' occurred in Mono.Data.Sqlite.dll but was not handled in user code
Additional information: The method or operation is not implemented.
ImageError
Connection Extra Information
The last picture, it may give more information....
Thank you all in advance :)
I've found the solution,I hope it helps the people that may be looking for the same as I.
Just go to Nuget - And download the Portable.Data.Sqlite that relies on SQLitePCL (Latest version) .
This package (Portable.Data.Sqlite) it will use the connection and will create SqliteDataReader and other property's that we are used to use .
This will work on Visual Studio 2015 and the project must be in framework 4.51 +=
----Error Tips----
if you encounter this error : Cant use Temporary Database or Path, just download Sqlite.dll and place on the project BIN folder and System32/ SysWoW64 .
I have a very unusual problem.
I'm trying to create a simple database (6 tables, 4 of which only have 2 columns).
I'm using an in-house database library which I've used in a previous project, and it does work.
However with my current project there are occasional bugs. Basically the database isn't created correctly. It is added to the sdcard but when I access it I get a DatabaseException.
When I access the device from the desktop manager and try to open the database (with SQLite Database Browser v2.0b1) I get "File is not a SQLite 3 database".
UPDATE
I found that this happens when I delete the database manually off the sdcard.
Since there's no way to stop a user doing that, is there anything I can do to handle it?
CODE
public static boolean initialize()
{
boolean memory_card_available = ApplicationInterface.isSDCardIn();
String application_name = ApplicationInterface.getApplicationName();
if (memory_card_available == true)
{
file_path = "file:///SDCard/" + application_name + ".db";
}
else
{
file_path = "file:///store/" + application_name + ".db";
}
try
{
uri = URI.create(file_path);
FileClass.hideFile(file_path);
} catch (MalformedURIException mue)
{
}
return create(uri);
}
private static boolean create(URI db_file)
{
boolean response = false;
try
{
db = DatabaseFactory.create(db_file);
db.close();
response = true;
} catch (Exception e)
{
}
return response;
}
My only suggestion is keep a default database in your assets - if there is a problem with the one on the SD Card, attempt to recreate it by copying the default one.
Not a very good answer I expect.
Since it looks like your problem is that the user is deleting your database, just make sure to catch exceptions when you open it (or access it ... wherever you're getting the exception):
try {
URI uri = URI.create("file:///SDCard/Databases/database1.db");
sqliteDB = DatabaseFactory.open(myURI);
Statement st = sqliteDB.createStatement( "CREATE TABLE 'Employee' ( " +
"'Name' TEXT, " +
"'Age' INTEGER )" );
st.prepare();
st.execute();
} catch ( DatabaseException e ) {
System.out.println( e.getMessage() );
// TODO: decide if you want to create a new database here, or
// alert the user if the SDCard is not available
}
Note that even though it's probably unusual for a user to delete a private file that your app creates, it's perfectly normal for the SDCard to be unavailable because the device is connected to a PC via USB. So, you really should always be testing for this condition (file open error).
See this answer regarding checking for SDCard availability.
Also, read this about SQLite db storage locations, and make sure to review this answer by Michael Donohue about eMMC storage.
Update: SQLite Corruption
See this link describing the many ways SQLite databases can be corrupted. It definitely sounded to me like maybe the .db file was deleted, but not the journal / wal file. If that was it, you could try deleting database1* programmatically before you create database1.db. But, your comments seem to suggest that it was something else. Perhaps you could look into the file locking failure modes, too.
If you are desperate, you might try changing your code to use a different name (e.g. database2, database3) each time you create a new db, to make sure you're not getting artifacts from the previous db.
Database that already exists is replaced by calling the method CreateTable <> in SQLite for Windows 8, erasing all the lines and creating a new table. How can I solve? following code to analyze:
using(var db = new SQLite.SQLiteConnection(App.DBPath))
{
db.CreateTable<ListasEntid>();
if (db.ExecuteScalar<int>("select count(1) from ListasEntid")==0)
{
db.RunInTransaction(() =>
{
db.Insert(new ListasEntid() { Nome = "Lista", Eletros = "Teste" });
});
}
}
Not sure what language you are using, but if you can execute raw SQL then you can use the following syntax:
CREATE TABLE IF NOT EXISTS ListasEntid (nome text, eletros text);
This ensures that table ListasEntid exists without nuking any of your previous data.
Thank you for the attention, but the problem was not specifically CreateTable method, but in the application configuration in the application properties, Debug tab, in option start the box was marked, "Unistall and then re-install my packege", erasing all files always initializing the debug.
I have a lot of XSL files in my ASP.NET web app. A lot. I generate a bunch of AJAX HTML responses using this kind of generic transform method:
public void Transform(XmlDocument xml, string xslPath)
{
...
XslTransform myXslTrans = new XslTransform();
myXslTrans.Load(xslPath);
myXslTrans.Transform(xml,null, HttpContext.Current.Response.Output);
}
I'd like to move the XSL definitions into SQL Server, using a column of type xml.
I would store an entire XSL file in a single row in SQL, and each XSL is self-contained (no imports). I would read out the XSL definition from SQL into my XslTransform object.
Something like this:
public void Transform(XmlDocument xml, string xslKey)
{
...
SqlCommand cmd = new SqlCommand("GetXslDefinition");
cmd.AddParameter("#xslKey", SqlDbType.VarChar).Value = xslKey;
// where the result set has a single column of XSL: "<xslt:stylesheet>..."
...
SqlDataReader dr = cmd.ExecuteReader();
if(dr.Read()) {
SqlXml xsl = dr.GetSqlXml(0);
XslTransform myXslTrans = new XslTransform();
myXslTrans.Load(xsl.CreateReader());
myXslTrans.Transform(xml,null, HttpContext.Current.Response.Output);
}
}
It seems like a straightforward way to:
add metadata to each XSL, like lastUsed, useCount, etc.
bulk update/search capabilities
prevent lots of disk access
avoid referencing relative paths and organizing files
allow XSL changes without redeploying (I could even write an admin page that selects/updates the XSL in the database)
Has anyone tried this before? Are there any caveats?
EDIT
Caveats that responders have listed:
disk access isn't guaranteed to diminish
this will break xsl:includes
The two big issues I can see are:
We use a lot of includes to ensure that we only do things once, storing the XSLT in the database would stop us from doing that.
It makes updating XSLs more interesting - we've been quite happy to dump new .xsl files into deployed sites without doing a full update of the site. For that matter we've got bits of code that look for client specific xsl in a folder and those bits of code can reach back up to common code (templates) in the root - so I'm not sure about the redeploy thing at all, but this will depend very much on the particular use case, yours is certainly different to ours.
In terms of disk access, hmm... the db still has to go access the disk to pull the data and if you're talking about caching then the db isn't a requirement for enabling caching.
Have to agree about the update/search options - you can do stuff with Powershell but that needs to be run on the server and that's not always a good idea.
Technically I can see no reason why not (excepting the wish to do includes as above) but practically it seems to be fairly balanced with good arguments either way.
I store XSLTs in a database in my application dbscript. (However I keep them in an NVARCHAR column, since it also runs on SQL Server 2000)
Since users are able to edit their XSLTs, I needed to write a custom validator which loads the text of TextBox in a .Net XslCompiledTransform object like this:
args.IsValid = true;
if (args.Value.Trim() == "")
return;
try
{
System.IO.TextReader rd = new System.IO.StringReader(args.Value);
System.Xml.XmlReader xrd = System.Xml.XmlReader.Create(rd);
System.Xml.Xsl.XslCompiledTransform xslt = new System.Xml.Xsl.XslCompiledTransform();
System.Xml.Xsl.XsltSettings xslts = new System.Xml.Xsl.XsltSettings(false, false);
xslt.Load(xrd, xslts, new System.Xml.XmlUrlResolver());
xrd.Close();
}
catch (Exception ex)
{
this.ErrorMessage = (string.IsNullOrEmpty(sErrorMessage) ? "" : (sErrorMessage + "<br/>") +
ex.Message);
if (ex.InnerException != null)
{
ex = ex.InnerException;
this.ErrorMessage += "<br />" + ex.Message;
}
args.IsValid = false;
}
As for your points:
file I/O will be replaced by database-generated disk I/O, so no gains there
deployment changes to providing an INSERT/UPDATE script containing the new data