I am trying to use the following code but it's says invalid constructor ColumnSliceIterator
SliceQuery<String, UUID, String> query = HFactory
.createSliceQuery(keyspaceOperator, StringSerializer.get(),
UUIDSerializer.get(), StringSerializer.get())
.setKey(login).setColumnFamily(FRIENDS_CF);
ColumnSliceIterator<String , UUID, String> iterator = new ColumnSliceIterator<String, UUID, String>(query, null, "\uFFFF", false);
How can i fix this?
SliceQuery<String, UUID, String> query = HFactory
.createSliceQuery(keyspaceOperator, StringSerializer.get(),
UUIDSerializer.get(), StringSerializer.get())
.setKey(login).setColumnFamily(FRIENDS_CF);
ColumnSliceIterator.ColumnSliceFinish<UUID> FINISH = new ColumnSliceIterator.ColumnSliceFinish<UUID>() {
#Override
public UUID function() {
return TimeUUIDUtils.getUniqueTimeUUIDinMillis();
}
};
ColumnSliceIterator<String, UUID, String> iterator = new ColumnSliceIterator<String, UUID, String>(query, null, FINISH, false, 100);
List<String> friendIds = new LinkedList<String>();
while (iterator.hasNext()) {
friendIds.add(iterator.next().getName().toString());
}
return friendIds;
Related
Here's the error I get:
E/SQLiteLog(25090): (1) near "#gmail": syntax error .
It seems like there is a problem in email input.
I guess there is nothing wrong in the creating of database.
creating db:
class UsersTable {
static const String tableName = 'Users';
static const String id = 'id';
static const String email = 'email';
static const String createQuery = '''
CREATE TABLE IF NOT EXISTS $tableName (
$id integer primary key autoincrement,
$email text not null unique);''';
}
in model class:
class Users {
late final int id;
late String email;
Users({
required this.id,
required this.email,
});
Users.fromDb(Map<String, dynamic> map) {
id = map[UsersTable.id];
email = map[UsersTable.email];
}
}
in UserService class which I think is where the problem arise:
class UserService {
...
Future<Users> getOrCreateUser({
required String email,
bool setAsCurrentUser = true,
}) async {
try {
//we found the user
final user = await getUser(email: email);
if (setAsCurrentUser) {
_user = user;
}
return user;
} on CouldNotFindUser {
//we didn't find the user
final createdUser = await createUser(email: email);
if (setAsCurrentUser) {
_user = createdUser;
}
return createdUser;
} catch (e) {
rethrow;
}
}
Future<Users> getUser({required String email}) async {
await _ensureDbIsOpen();
final db = _getDatabaseOrThrow();
final results = await db.query(
UsersTable.tableName,
limit: 1,
where: 'email = ?',
whereArgs: [email.toLowerCase()],
);
if (results.isEmpty) {
throw CouldNotFindUser();
} else {
return Users.fromDb(results.first);
}
}
...}
in main class:
...
Widget build(BuildContext context) {
return FutureBuilder(
future: _userService.getOrCreateUser(email: userEmail),
builder: (context, snapshot) {
return Provider(
create: (ctx) => HomePageController(),
dispose: (ctx, HomePageController controller) =>
...
how can I solve this error?
I use Room in my Android Studio App, the Code A will crash when no record exists to query
What happens if no records exists when I use Room to query with Code B ?
#Dao
interface RecordDao {
// Code A
#Query("SELECT * FROM record_table where id=:id")
fun getByID(id:Int): Flow<RecordEntity>
// Code B
#Query("SELECT * FROM record_table")
fun getAll(): Flow<List<RecordEntity>>
}
If you look at the code generated by room for the RecordDao_Impl class implementation of RecordDao, you'll notice multiple things:
The getById function code returns null when no matching records exist in the table, and since your 'Code A' function return type is not null, kotlin throws a NullPointerException for the first function.
The getAll function code returns a Flow object with an ArrayList, in case it found any records then it adds them to the list, otherwise it just emits the empty ArrayList to the Flow object, therefore, you'll always get a flow object with a list inside it regardless if room found matching records or not, so no exception is thrown.
You can understand this a bit more if you look at the code generated for the two functions here:
#Override
public Flow<RecordEntity> getByID(final int id) {
final String _sql = "SELECT * FROM record_table where id=?";
final RoomSQLiteQuery _statement = RoomSQLiteQuery.acquire(_sql, 1);
int _argIndex = 1;
_statement.bindLong(_argIndex, id);
return CoroutinesRoom.createFlow(__db, false, new String[]{"record_table"}, new Callable<RecordEntity>() {
#Override
public RecordEntity call() throws Exception {
final Cursor _cursor = DBUtil.query(__db, _statement, false, null);
try {
final int _cursorIndexOfId = CursorUtil.getColumnIndexOrThrow(_cursor, "id");
final RecordEntity _result;
if (_cursor.moveToFirst()) {
final int _tmpId;
_tmpId = _cursor.getInt(_cursorIndexOfId);
_result = new RecordEntity(_tmpId);
} else {
_result = null;
}
return _result;
} finally {
_cursor.close();
}
}
#Override
protected void finalize() {
_statement.release();
}
});
}
#Override
public Flow<List<RecordEntity>> getAll() {
final String _sql = "SELECT * FROM record_table";
final RoomSQLiteQuery _statement = RoomSQLiteQuery.acquire(_sql, 0);
return CoroutinesRoom.createFlow(__db, false, new String[]{"record_table"}, new Callable<List<RecordEntity>>() {
#Override
public List<RecordEntity> call() throws Exception {
final Cursor _cursor = DBUtil.query(__db, _statement, false, null);
try {
final int _cursorIndexOfId = CursorUtil.getColumnIndexOrThrow(_cursor, "id");
final List<RecordEntity> _result = new ArrayList<RecordEntity>(_cursor.getCount());
while (_cursor.moveToNext()) {
final RecordEntity _item;
final int _tmpId;
_tmpId = _cursor.getInt(_cursorIndexOfId);
_item = new RecordEntity(_tmpId);
_result.add(_item);
}
return _result;
} finally {
_cursor.close();
}
}
#Override
protected void finalize() {
_statement.release();
}
});
}
I've got some configuration values in a JSON file which I want to parse via gson to a data-class. I want to generate a new class, based on the created data-class where the values are final.
This all should happen during my CI-Pipeline and the generated class should then be used when my application is running.
Simple example to clarify:
I've got this data class
data class MyDataClass(val name:String, val age:Int)
and via parsing (gson) a instance like this is created
MyDataClass("john", 42)
Is there a way to create a (data) class based on the new instance of MyDataClass so anything like this will be created?
class MyDataClassFinal{
val name = "john"
val age = 42
}
Use .copy() and modify only the parameters you need to. For example:
val joe = MyDataClass(“Joe”, 42)
val mary = joe.copy(name = “Mary”) // age is 42
I've got some configuration values in a json file wich I want to parse via gson to a data-class. I want to generate a new class, based on the created data-class where the values are final.
There is nothing for you to do here. The data class, as you've described it, is final. It is not open so the class is final and the fields are vals and only set via constructor, so they can't be changed, so they too are final.
You can see the Java equivalent of the class by going to doing a search for "Actions", looking for Kotlin Bytecode, then hit Decompile to see the Java source. It looks like this:
#Metadata(
mv = {1, 1, 18},
bv = {1, 0, 3},
k = 1,
d1 = {"\u0000 \n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0000\n\u0002\u0010\u000e\n\u0000\n\u0002\u0010\b\n\u0002\b\t\n\u0002\u0010\u000b\n\u0002\b\u0004\b\u0086\b\u0018\u00002\u00020\u0001B\u0015\u0012\u0006\u0010\u0002\u001a\u00020\u0003\u0012\u0006\u0010\u0004\u001a\u00020\u0005¢\u0006\u0002\u0010\u0006J\t\u0010\u000b\u001a\u00020\u0003HÆ\u0003J\t\u0010\f\u001a\u00020\u0005HÆ\u0003J\u001d\u0010\r\u001a\u00020\u00002\b\b\u0002\u0010\u0002\u001a\u00020\u00032\b\b\u0002\u0010\u0004\u001a\u00020\u0005HÆ\u0001J\u0013\u0010\u000e\u001a\u00020\u000f2\b\u0010\u0010\u001a\u0004\u0018\u00010\u0001HÖ\u0003J\t\u0010\u0011\u001a\u00020\u0005HÖ\u0001J\t\u0010\u0012\u001a\u00020\u0003HÖ\u0001R\u0011\u0010\u0004\u001a\u00020\u0005¢\u0006\b\n\u0000\u001a\u0004\b\u0007\u0010\bR\u0011\u0010\u0002\u001a\u00020\u0003¢\u0006\b\n\u0000\u001a\u0004\b\t\u0010\n¨\u0006\u0013"},
d2 = {"Lcore/lib/extensions/MyDataClass;", "", "name", "", "age", "", "(Ljava/lang/String;I)V", "getAge", "()I", "getName", "()Ljava/lang/String;", "component1", "component2", "copy", "equals", "", "other", "hashCode", "toString", "treking-android.dominicore-android"}
)
public final class MyDataClass {
#NotNull
private final String name;
private final int age;
#NotNull
public final String getName() {
return this.name;
}
public final int getAge() {
return this.age;
}
public MyDataClass(#NotNull String name, int age) {
Intrinsics.checkParameterIsNotNull(name, "name");
super();
this.name = name;
this.age = age;
}
#NotNull
public final String component1() {
return this.name;
}
public final int component2() {
return this.age;
}
#NotNull
public final MyDataClass copy(#NotNull String name, int age) {
Intrinsics.checkParameterIsNotNull(name, "name");
return new MyDataClass(name, age);
}
// $FF: synthetic method
public static MyDataClass copy$default(MyDataClass var0, String var1, int var2, int var3, Object var4) {
if ((var3 & 1) != 0) {
var1 = var0.name;
}
if ((var3 & 2) != 0) {
var2 = var0.age;
}
return var0.copy(var1, var2);
}
#NotNull
public String toString() {
return "MyDataClass(name=" + this.name + ", age=" + this.age + ")";
}
public int hashCode() {
String var10000 = this.name;
return (var10000 != null ? var10000.hashCode() : 0) * 31 + this.age;
}
public boolean equals(#Nullable Object var1) {
if (this != var1) {
if (var1 instanceof MyDataClass) {
MyDataClass var2 = (MyDataClass)var1;
if (Intrinsics.areEqual(this.name, var2.name) && this.age == var2.age) {
return true;
}
}
return false;
} else {
return true;
}
}
}
As you can see, the class, it's fields, and their accessors are all final.
I am using cosmos db to store and fetch data. Previously I was using DocumentClient like:
public class ProductRepository : IProductRepository
{
private DocumentClient _documentClient;
private DocumentCollection _graphCollection;
public ProductRepository(DocumentClient documentClient, DocumentCollection graphCollection)
{
_documentClient = documentClient;
_graphCollection = graphCollection;
}
public async Task Create(Product product)
{
var createQuery = CreateQuery(product);
IDocumentQuery<dynamic> query = _documentClient.CreateGremlinQuery<dynamic>(_graphCollection, createQuery);
if(query.HasMoreResults)
{
await query.ExecuteNextAsync();
}
}
public async Task<Product> Get(string id)
{
Product product = null;
var getQuery = #"g.V('" + id + "')";
var query = _documentClient.CreateGremlinQuery<dynamic>(_graphCollection, getQuery);
if (query.HasMoreResults)
{
var result = await query.ExecuteNextAsync();
if (result.Count == 0)
return product;
var productData = (JObject)result.FirstOrDefault();
product = new Product
{
name = productData["name"].ToString()
};
}
return product;
}
}
}
But it is not unit testable so I want to convert it to IDocumentClient but IDocumentClient doesn't contain definition for CreateGremlinQuery. So what is the best possible way to convert my methods so that they will be using IDocumentClient? Do I need to use CreateDocumentQuery? if yes, how can I convert CreateGremlimQuery to CreateDocumentQuery?
There are several ways to get around that. The simplest one would be to simply hard cast your IDocumentClient to DocumentClient.
If you go with that approach your code becomes:
public class ProductRepository : IProductRepository
{
private IDocumentClient _documentClient;
private DocumentCollection _graphCollection;
public ProductRepository(IDocumentClient documentClient, DocumentCollection graphCollection)
{
_documentClient = documentClient;
_graphCollection = graphCollection;
}
public async Task Create(Product product)
{
var createQuery = CreateQuery(product);
IDocumentQuery<dynamic> query = ((DocumentClient)_documentClient).CreateGremlinQuery<dynamic>(_graphCollection, createQuery);
if(query.HasMoreResults)
{
await query.ExecuteNextAsync();
}
}
public async Task<Product> Get(string id)
{
Product product = null;
var getQuery = #"g.V('" + id + "')";
var query = ((DocumentClient)_documentClient).CreateGremlinQuery<dynamic>(_graphCollection, getQuery);
if (query.HasMoreResults)
{
var result = await query.ExecuteNextAsync();
if (result.Count == 0)
return product;
var productData = (JObject)result.FirstOrDefault();
product = new Product
{
name = productData["name"].ToString()
};
}
return product;
}
}
You could also create your own extensions for IDocumentClient.
public static class MoreGraphExtensions
{
public static IDocumentQuery<T> CreateGremlinQuery<T>(this IDocumentClient documentClient, DocumentCollection collection, string gremlinExpression, FeedOptions feedOptions = null, GraphSONMode graphSONMode = GraphSONMode.Compact)
{
return GraphExtensions.CreateGremlinQuery<T>((DocumentClient)documentClient, collection, gremlinExpression, feedOptions, graphSONMode);
}
public static IDocumentQuery<object> CreateGremlinQuery(this IDocumentClient documentClient, DocumentCollection collection, string gremlinExpression, FeedOptions feedOptions = null, GraphSONMode graphSONMode = GraphSONMode.Compact)
{
return GraphExtensions.CreateGremlinQuery<object>((DocumentClient)documentClient, collection, gremlinExpression, feedOptions, graphSONMode);
}
}
It is a pre-release however, so I do think that Microsoft will get around moving the extension methods at the interface level.
Hello I have SQL server with setting up always encrypted feature, also I setup EF for work with always encrypted columns, but when I try to add/update, for Db manipulation I use DbContext, entry in my Db I get follow error:
Operand type clash: decimal(1,0) encrypted with (encryption_type = 'DETERMINISTIC', encryption_algorithm_name = 'AEAD_AES_256_CBC_HMAC_SHA_256', column_encryption_key_name = '****', column_encryption_key_database_name = '****') is incompatible with decimal(6,2) encrypted with (encryption_type = 'DETERMINISTIC', encryption_algorithm_name = 'AEAD_AES_256_CBC_HMAC_SHA_256', column_encryption_key_name = '*****', column_encryption_key_database_name = '****')
Model that I use
public class Model
{
/// <summary>
/// Payment method name
/// </summary>
[Column(TypeName = "nvarchar(MAX)")]
public string Name { get; set; }
/// <summary>
/// Payment method description
/// </summary>
[Column(TypeName = "nvarchar(MAX)")]
public string Description { get; set; }
/// <summary>
/// Fee charges for using payment method
/// </summary>
[Column(TypeName = "decimal(6,2)")]
public decimal Fee { get; set; }
}
Also I tried to specify decimal format in OnModelCreating method
builder.Entity<Model>().Property(x => x.Fee).HasColumnType("decimal(6,2)");
What I missed ?
Thanks for any advice
My colleague and I have found a workaround to the problem using the DiagnosticSource.
You must know that:
Entity Framework Core hooks itself into DiagnosticSource.
DiagnosticSource uses the observer pattern to notify its observers.
The idea is to populate the 'Precision' and 'Scale' fields of the command object (created by EFCore), in this way the call made to Sql will contain all the information necessary to correctly execute the query.
First of all, create the listener:
namespace YOUR_NAMESPACE_HERE
{
public class EfGlobalListener : IObserver<DiagnosticListener>
{
private readonly CommandInterceptor _interceptor = new CommandInterceptor();
public void OnCompleted()
{
}
public void OnError(Exception error)
{
}
public void OnNext(DiagnosticListener value)
{
if (value.Name == DbLoggerCategory.Name)
{
value.Subscribe(_interceptor);
}
}
}
}
Where CommandInterceptor is:
namespace YOUR_NAMESPACE_HERE
{
public class CommandInterceptor : IObserver<KeyValuePair<string, object>>
{
// This snippet of code is only as example, you could maybe use Reflection to retrieve Field mapping instead of using Dictionary
private Dictionary<string, (byte Precision, byte Scale)> _tableMapping = new Dictionary<string, (byte Precision, byte Scale)>
{
{ "Table1.DecimalField1", (18, 2) },
{ "Table2.DecimalField1", (12, 6) },
{ "Table2.DecimalField2", (10, 4) },
};
public void OnCompleted()
{
}
public void OnError(Exception error)
{
}
public void OnNext(KeyValuePair<string, object> value)
{
if (value.Key == RelationalEventId.CommandExecuting.Name)
{
// After that EF Core generates the command to send to the DB, this method will be called
// Cast command object
var command = ((CommandEventData)value.Value).Command;
// command.CommandText -> contains SQL command string
// command.Parameters -> contains all params used in sql command
// ONLY FOR EXAMPLE PURPOSES
// This code may contain errors.
// It was written only as an example.
string table = null;
string[] columns = null;
string[] parameters = null;
var regex = new Regex(#"^INSERT INTO \[(.+)\] \((.*)\)|^VALUES \((.*)\)|UPDATE \[(.*)\] SET (.*)$", RegexOptions.Multiline);
var matches = regex.Matches(command.CommandText);
foreach (Match match in matches)
{
if(match.Groups[1].Success)
{
// INSERT - TABLE NAME
table = match.Groups[1].Value;
}
if (match.Groups[2].Success)
{
// INSERT - COLS NAMES
columns = match.Groups[2].Value.Split(",", StringSplitOptions.RemoveEmptyEntries).Select(c => c.Replace("[", string.Empty).Replace("]", string.Empty).Trim()).ToArray();
}
if (match.Groups[3].Success)
{
// INSERT - PARAMS VALUES
parameters = match.Groups[3].Value.Split(",", StringSplitOptions.RemoveEmptyEntries).Select(c => c.Trim()).ToArray();
}
if (match.Groups[4].Success)
{
// UPDATE - TABLE NAME
table = match.Groups[4].Value;
}
if (match.Groups[5].Success)
{
// UPDATE - COLS/PARAMS NAMES/VALUES
var colParams = match.Groups[5].Value.Split(",", StringSplitOptions.RemoveEmptyEntries).Select(p => p.Replace("[", string.Empty).Replace("]", string.Empty).Trim()).ToArray();
columns = colParams.Select(cp => cp.Split('=', StringSplitOptions.RemoveEmptyEntries)[0].Trim()).ToArray();
parameters = colParams.Select(cp => cp.Split('=', StringSplitOptions.RemoveEmptyEntries)[1].Trim()).ToArray();
}
}
// After taking all the necessary information from the sql command
// we can add Precision and Scale to all decimal parameters
foreach (var item in command.Parameters.OfType<SqlParameter>().Where(p => p.DbType == DbType.Decimal))
{
var index = Array.IndexOf<string>(parameters, item.ParameterName);
var columnName = columns.ElementAt(index);
var key = $"{table}.{columnName}";
// Add Precision and Scale, that fix our problems w/ always encrypted columns
item.Precision = _tableMapping[key].Precision;
item.Scale = _tableMapping[key].Scale;
}
}
}
}
}
Finally add in the Startup.cs the following line of code to register the listener:
DiagnosticListener.AllListeners.Subscribe(new EfGlobalListener());
Ecountered the same issue.
Adjusted #SteeBono interceptor to work with commands which contain multiple statements:
public class AlwaysEncryptedDecimalParameterInterceptor : DbCommandInterceptor, IObserver<KeyValuePair<string, object>>
{
private Dictionary<string, (SqlDbType DataType, byte? Precision, byte? Scale)> _decimalColumnSettings =
new Dictionary<string, (SqlDbType DataType, byte? Precision, byte? Scale)>
{
// MyTableDecimal
{ $"{nameof(MyTableDecimal)}.{nameof(MyTableDecimal.MyDecimalColumn)}", (SqlDbType.Decimal, 18, 6) },
// MyTableMoney
{ $"{nameof(MyTableMoney)}.{nameof(MyTableMoney.MyMoneyColumn)}", (SqlDbType.Money, null, null) },
};
public void OnCompleted()
{
}
public void OnError(Exception error)
{
}
// After that EF Core generates the command to send to the DB, this method will be called
public void OnNext(KeyValuePair<string, object> value)
{
if (value.Key == RelationalEventId.CommandExecuting.Name)
{
System.Data.Common.DbCommand command = ((CommandEventData)value.Value).Command;
Regex regex = new Regex(#"INSERT INTO \[(.+)\] \((.*)\)(\r\n|\r|\n)+VALUES \(([^;]*)\);|UPDATE \[(.*)\] SET (.*)|MERGE \[(.+)\] USING \((\r\n|\r|\n)+VALUES \(([^A]*)\) AS \w* \((.*)\)");
MatchCollection matches = regex.Matches(command.CommandText);
foreach (Match match in matches)
{
(string TableName, string[] Columns, string[] Params) commandComponents = GetCommandComponents(match);
int countOfColumns = commandComponents.Columns.Length;
// After taking all the necessary information from the sql command
// we can add Precision and Scale to all decimal parameters and set type for Money ones
for (int index = 0; index < commandComponents.Params.Length; index++)
{
SqlParameter decimalSqlParameter = command.Parameters.OfType<SqlParameter>()
.FirstOrDefault(p => commandComponents.Params[index] == p.ParameterName);
if (decimalSqlParameter == null)
{
continue;
}
string columnName = commandComponents.Columns.ElementAt(index % countOfColumns);
string settingKey = $"{commandComponents.TableName}.{columnName}";
if (_decimalColumnSettings.ContainsKey(settingKey))
{
(SqlDbType DataType, byte? Precision, byte? Scale) settings = _decimalColumnSettings[settingKey];
decimalSqlParameter.SqlDbType = settings.DataType;
if (settings.Precision.HasValue)
{
decimalSqlParameter.Precision = settings.Precision.Value;
}
if (settings.Scale.HasValue)
{
decimalSqlParameter.Scale = settings.Scale.Value;
}
}
}
}
}
}
private (string TableName, string[] Columns, string[] Params) GetCommandComponents(Match match)
{
string tableName = null;
string[] columns = null;
string[] parameters = null;
// INSERT
if (match.Groups[1].Success)
{
tableName = match.Groups[1].Value;
columns = match.Groups[2].Value.Split(",", StringSplitOptions.RemoveEmptyEntries)
.Select(c => c.Replace("[", string.Empty)
.Replace("]", string.Empty)
.Trim()).ToArray();
parameters = match.Groups[4].Value
.Split(",", StringSplitOptions.RemoveEmptyEntries)
.Select(c => c.Trim()
.Replace($"),{Environment.NewLine}(", string.Empty)
.Replace("(", string.Empty)
.Replace(")", string.Empty))
.ToArray();
return (
TableName: tableName,
Columns: columns,
Params: parameters);
}
// UPDATE
if (match.Groups[5].Success)
{
tableName = match.Groups[5].Value;
string[] colParams = match.Groups[6].Value.Split(",", StringSplitOptions.RemoveEmptyEntries)
.Select(p => p.Replace("[", string.Empty).Replace("]", string.Empty).Trim())
.ToArray();
columns = colParams.Select(cp => cp.Split('=', StringSplitOptions.RemoveEmptyEntries)[0].Trim()).ToArray();
parameters = colParams.Select(cp => cp.Split('=', StringSplitOptions.RemoveEmptyEntries)[1].Trim()).ToArray();
return (
TableName: tableName,
Columns: columns,
Params: parameters);
}
// MERGE
if (match.Groups[7].Success)
{
tableName = match.Groups[7].Value;
parameters = match.Groups[9].Value.Split(",", StringSplitOptions.RemoveEmptyEntries)
.Select(c => c.Trim()
.Replace($"),{Environment.NewLine}(", string.Empty)
.Replace("(", string.Empty)
.Replace(")", string.Empty))
.ToArray();
columns = match.Groups[10].Value.Split(",", StringSplitOptions.RemoveEmptyEntries).Select(c => c.Replace("[", string.Empty).Replace("]", string.Empty).Trim()).ToArray();
return (
TableName: tableName,
Columns: columns,
Params: parameters);
}
throw new Exception($"{nameof(AlwaysEncryptedDecimalParameterInterceptor)} was not able to parse the command");
}
}