I have the following piece of code:
rocksdb::DBWithTTL* db = ...
rocksdb::WriteOptions writeOptions;
rocksdb::ColumnFamilyHandle cfHandle = ...
std::string keyPrefix = "prefix";
std::string key = keyPrefix + "_key";
std::string value = "value";
rocksdb::Status s = db->Put(writeOptions, cfHandle, key, value);
rocksdb::ReadOptions readOptions;
readOptions.prefix_same_as_start;
readOptions.snapshot = db->GetSnapshot();
rocksdb::Iterator* iterator = db->NewIterator(readOptions);
rocksdb::Sliced start = rocksdb::Slice(keyPrefix);
for (iterator->Seek(start); iterator->Valid(); iterator->Next()) {
printf("hello");
}
The printf is never hit.
However, if I change the Put line to:
rocksdb::Status s = db->Put(writeOptions, key, value);
Meaning, removing the column family handle, I'm getting the line printed fine.
I'm guessing the iterator API should take the column family into account, but I couldn't find any documentation.
Indeed the missing API call was:
rocksdb::Iterator* iterator = db->NewIterator(readOptions, cfHandle);
Related
I am trying to use isolationforest in weka ,but I cannot find a easy example which shows how to use it ,who can help me ?thanks in advance
import weka.classifiers.misc.IsolationForest;
public class Test2 {
public static void main(String[] args) {
IsolationForest isolationForest = new IsolationForest();
.....................................................
}
}
I strongly suggest you to study a little bit the implementation for IslationForest.
The following code work loading a CSV file with first column with Class (note: a single class value will produce only (1-anomaly score) if it's binary you will get the anomaly score too. Otherwise it just return an error). Note I skip the second column (that in my case is the uuid that is not needed for anomaly detection)
private static void findOutlier(File in, File out) throws Exception {
CSVLoader loader = new CSVLoader();
loader.setSource(new File(in.getAbsolutePath()));
Instances data = loader.getDataSet();
// setting class attribute if the data format does not provide this information
// For example, the XRFF format saves the class attribute information as well
if (data.classIndex() == -1)
data.setClassIndex(0);
String[] options = new String[2];
options[0] = "-R"; // "range"
options[1] = "2"; // first attribute
Remove remove = new Remove(); // new instance of filter
remove.setOptions(options); // set options
remove.setInputFormat(data); // inform filter about dataset **AFTER** setting options
Instances newData = Filter.useFilter(data, remove); // apply filter
IsolationForest randomForest = new IsolationForest();
randomForest.buildClassifier(newData);
// System.out.println(randomForest);
FileWriter fw = new FileWriter(out);
final Enumeration<Attribute> attributeEnumeration = data.enumerateAttributes();
for (Attribute e = attributeEnumeration.nextElement(); attributeEnumeration.hasMoreElements(); e = attributeEnumeration.nextElement()) {
fw.write(e.name());
fw.write(",");
}
fw.write("(1 - anomaly score),anomaly score\n");
for (int i = 0; i < data.size(); ++i) {
Instance inst = data.get(i);
final double[] distributionForInstance = randomForest.distributionForInstance(inst);
fw.write(inst + ", " + distributionForInstance[0] + "," + (1 - distributionForInstance[0]));
fw.write(",\n");
}
fw.flush();
}
The previous function will add at the CSV at last column the anomaly values. Please note I'm using a single class so for getting the corresponding anomaly I do 1 - distributionForInstance[0] otherwise you ca do simply distributionForInstance[1] .
A sample input.csv for getting (1-anomaly score):
Class,ignore, feature_0, feature_1, feature_2
A,1,21,31,31
A,2,41,61,81
A,3,61,37,34
A sample input.csv for getting (1-anomaly score) and anomaly score:
Class,ignore, feature_0, feature_1, feature_2
A,1,21,31,31
B,2,41,61,81
A,3,61,37,34
So, basically all this code does is search the database for a user with a certain username and password, and returns a nullptr if it doesn't find one.
Gebruiker* Gebruiker_DAO::getGebruiker(string login, string wachtwoord)
{
PreparedStatement *prep_stmt = nullptr;
ResultSet *res = nullptr;
Gebruiker* gebruiker = nullptr;
int rowcount = 0;
try {
prep_stmt = dbConn->getConnection()->prepareStatement("SELECT * FROM Gebruiker WHERE Gebruiker_login = ? AND Gebruiker_wachtwoord = ?");
prep_stmt->setString(1, login);
prep_stmt->setString(2, wachtwoord);
res = prep_stmt->executeQuery();
while (res->next()) {
gebruiker = new Gebruiker(login, res->getBoolean("Gebruiker_isAdmin"), res->getString("Bedrijf"),res->getBoolean("Gebruiker_isActief"),res->getInt("Werknemer_ID"));
}
}
catch(SQLException& e) {
console.log(e.what(), console.Error);
return nullptr;
}
return gebruiker;
}
The issue is that setString throws an "std::bad_alloc at memory location ..."
Ive noticed before that trying to put a string in an SQLString also throws an error. Until now ive used a workaround by putting stuff in SQLStrings.
SQLString schema = "groep003B";
dbConn->getInstance()->setSchema(schema);
dbConn->getInstance()->connect();
For some weird reason this DOES work...
Is there something i am doing wrong? I have seen examples where people use strings, but for some reason this does not work for me... Every time i try to put a variable std::string in an SQLString it gives a memory issue.
I am trying to update a record in one of my Azure Mobile tables using the “update” function in the azure mobile C++ header. But I get an exception. Below is what my code looks like:
void DBUtils::DBQuestion::UpdateQuestionInTable(std::shared_ptr<azure::mobile::table> table)
{
auto obj = json::value::object();
obj[U("id")] = json::value::string(ID);
obj[U("QuestionText")] = json::value::string(QuestionText);
obj[U("AnswerLatitude")] = json::value::number(AnswerLatitude);
obj[U("AnswerLongitude")] = json::value::number(AnswerLongitude);
table->update(obj);
}
I have verified that the ID above is a valid one actually present in the table. A similar insert operation (which doesn’t specify the ID field) actually succeeds:
void DBUtils::DBQuestion::InsertIntoTable(std::shared_ptr<azure::mobile::table> table)
{
auto obj = json::value::object();
obj[U("QuestionText")] = json::value::string(QuestionText);
obj[U("AnswerLatitude")] = json::value::number(AnswerLatitude);
obj[U("AnswerLongitude")] = json::value::number(AnswerLongitude);
table->insert(obj);
}
What am I doing wrong?
Azure Mobile recently updated its table schema so that the Id field is now a string, which gets filled in by the server with a Guid value if the client doesn’t set it.
This change has introduced a bug in the C++ library. As a workaround, you can try calling the other overload for update, the one that takes the ID string and the object.
void DBUtils::DBQuestion::UpdateQuestionInTable(utility::string_t id, std::shared_ptr<azure::mobile::table> table)
{
auto obj = json::value::object();
obj[U("QuestionText")] = json::value::string(QuestionText);
obj[U("AnswerLatitude")] = json::value::number(AnswerLatitude);
obj[U("AnswerLongitude")] = json::value::number(AnswerLongitude);
ID = id;
table->update(ID, obj);
}
I am able to retrieve database values and insert database values, but I can't figure out what the Update() syntax should be with a where statement.
Environment -> ASP.Net, C#
Settings.ttinclude
const string Namespace = "subsonic_db.Data";
const string ConnectionStringName = "subsonic_dbConnectionString";
//This is the name of your database and is used in naming
//the repository. By default we set it to the connection string name
const string DatabaseName = "subsonic_db";
Retreive example
var product = equipment.SingleOrDefault(x => x.id == 1);
Insert Example
equipment my_equipment = new equipment();
try
{
// insert
my_equipment.parent_id = 0;
my_equipment.primary_id = 0;
my_equipment.product_code = product_code.Text;
my_equipment.product_description = product_description.Text;
my_equipment.product_type_id = Convert.ToInt32(product_type_id.SelectedItem.Value);
my_equipment.created_date = DateTime.Now;
my_equipment.serial_number = serial_number.Text;
my_equipment.Save();
}
catch (Exception err)
{
lblError.Text = err.Message;
}
Edit: Think that I was just too tired last night, it is pretty easy to update. Just use the retrieve function and use the Update() on that.
var equip = Equipment.SingleOrDefault(x => x.id == 1);
lblGeneral.Text = equip.product_description;
equip.product_description = "Test";
equip.Update();
Resolved. View answer above.
I need to get the primary key for a row and then insert it into one of the other columns in a string.
So I've tried to do it something like this:
newsObj = new news();
newsObj.name = "test"
newsObj.Save();
newsObj.url = String.Format("blah.aspx?p={0}",newsObj.col_id);
newsObj.Save();
But it doesn't treat it as the same data object so newsObj.col_id always comes back as a zero. Is there another way of doing this? I tried this on another page and to get it to work I had to set newsObj.SetIsLoaded(true);
This is the actual block of code:
page p;
if (pageId > 0)
p = new page(ps => ps.page_id == pageId);
else
p = new page();
if (publish)
p.page_published = 1;
if (User.IsInRole("administrator"))
p.page_approved = 1;
p.page_section = staticParent.page_section;
p.page_name = PageName.Text;
p.page_parent = parentPageId;
p.page_last_modified_date = DateTime.Now;
p.page_last_modified_by = (Guid)Membership.GetUser().ProviderUserKey;
p.Add();
string urlString = String.Empty;
if (parentPageId > 0)
{
urlString = Regex.Replace(staticParent.page_url, "(.aspx).*$", "$1"); // We just want the static page URL (blah.aspx)
p.page_url = String.Format("{0}?p={1}", urlString, p.page_id);
}
p.Save();
If I hover the p.Save(); I can see the correct values in the object but the DB is never updated and there is no exception.
Thanks!
I faced the same problem with that :
po oPo = new po();
oPo.name ="test";
oPo.save(); //till now it works.
oPo.name = "test2";
oPo.save(); //not really working, it's not saving the data since isLoaded is set to false
and the columns are not considered dirty.
it's a bug in the ActiveRecord.tt for version 3.0.0.3.
In the method public void Add(IDataProvider provider)
immediately after SetIsNew(false);
there should be : SetIsLoaded(true);
the reason why the save is not working the second time is because the object can't get dirty if it is not loaded. By adding the SetIsLoaded(true) in the ActiveRecord.tt, when you are going to do run custom tool, it's gonna regenerate the .cs perfectly.