I Have a problem to fetch the data(item value and how to compare this item with anoher pagefrom SQLiteData Base ?
Cursor c=sq.rawQuery("select ClientId from RequestDriver where Date=? and FromTime=? and ToTime=?",null);
while(c.moveToNext()) {
int req=Integer.parseInt(reqId);
int ftime=Integer.parseInt(fromt);
int ttime=Integer.parseInt(tot);
int x=ttime-ftime;
int ty = c.getInt(c.getColumnIndex("ClientId"));
Intent intent = new Intent(this, AssignDriver.class);
startActivity(intent);
Related
Here is my code:
var emoji = "⭐";
var query = myContext.Products.Where(x => x.Name.Contains(emoji));
var queryString = query.ToQueryString();
var list = query.ToList();
Query returns all table records. If I replace contains to equal works great, but I have to search something like this:
"this is my emoji ⭐"
This is the SQL query:
DECLARE #__emoji_0 nvarchar(4000) = N'⭐'
SELECT [p].[Id], [p].[Name], [p].[Quantity]
FROM [Products] AS [p]
WHERE (#__emoji_0 LIKE N'') OR (CHARINDEX(#__emoji_0, [p].[Name]) > 0)
Is any way to do this in EF Core or raw SQL?
Your main issue is the fact that emojis and strings are represented differently.
Before you can search the emojis you will need to decide how are you gonna unify them both in search query and db.
First of all emojis are a pair of chars.What does that mean? Here as a quote from the Microsoft docs:
"🐂".Length = 2
s[0] = '�' ('\ud83d')
s[1] = '�' ('\udc02')
These examples show that the value of string.Length, which indicates the number of char instances, doesn't necessarily indicate the number of displayed characters. A single char instance by itself doesn't necessarily represent a character.
The char pairs that map to a single character are called surrogate pairs. To understand how they work, you need to understand Unicode and UTF-16 encoding.
Having this in mind I would go as follows:
Define a method which will convert emojis to a UTF16 string[] which will keep the two surrogate chars representation.
internal static string[] EmojiToUtf16Pair(string emoji)
{
string[] arr = new string[2];
for (int i = 0; i < emoji.Length; i++)
{
arr[i] = emoji[i].ToString();
}
return arr;
}
This could be use when you persist emojis in DB. Depending on how you decide to persist the emojis in DB some modification could be done for that method e.g. to return concatenated string or something like that.
I am not sure when, but for some reason you could use another method to do the reverse operation -> UTF16 to Emoji
internal static string UTF16PairToEmoji(string[] codes)
{
var test = string.Empty;
foreach (var i in codes)
{
test += i;
}
var result = test.ToString();
return result;
}
Here is all the code example:
class Program
{
static void Main()
{
var str = "🚴";
var utf16 = string.Join("",EmojiToUtf16Pair(str));
Console.WriteLine(utf16);
var testEmpoji = UTF16PairToEmoji(EmojiToUtf16Pair(str));
Console.WriteLine(testEmpoji);
}
internal static string[] EmojiToUtf16Pair(string emoji)
{
string[] arr = new string[2];
for (int i = 0; i < emoji.Length; i++)
{
arr[i] = emoji[i].ToString();
}
return arr;
}
internal static string UTF16PairToEmoji(string[] codes)
{
var test = string.Empty;
foreach (var i in codes)
{
test += i;
}
var result = test.ToString();
return result;
}
}
emoji ef-core db-query
You have to use like command
SELECT * FROM emoticon where emoji_utf like '👨🏫';
with EF in .net core
Emoticon emoticon=db_context.Emoticons.Where(a=>EF.Functions.Like(a.EmojiUtf,"%"+item.emojiString+"%" ) ).FirstOrDefault();
I was curious to know if there is an efficient way to store data into a container that has a maximum amount of values and when that value is reached it start removing the oldest values in order to add new ones. And all this in an ordered fashion (meaning that new data should come after the last new data).
I know I could achieve this using a queue
q.Enqueue(1);
q.Enqueue(2);
q.Enqueue(3); // 1 2 3
q.Dequeue(); // 2 3
q.Enqueue(4); // 2 3 4
but in order to iterate through the data afterwards requires to transform the queue in an array, which I'm not sure how efficient it is.
Maybe it's better to have an array with a fixed size and have an index that shifts to the start when the array is full and using some modulo magic iterate always backwards to query the data from most recent to less recent. This would be less readable but working and more efficient I guess.
So my question would be, is there a better more readable and efficient way?
And also, what is the efficiency of using ToArray() when using other data structures (e.g. List, Queue, Stack..). When should this be avoided?
At the end I decided to implement my idea. Not sure if this is the best way, but it works well for my needs:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class DataHolder<T> : IEnumerable
{
private T[] _data;
private int _maxSize;
private int _currIdx;
private int _currSize;
public DataHolder(int size)
{
_maxSize = size;
_data = new T[_maxSize];
_currIdx = -1;
_currSize = 0;
}
public void Add(T data)
{
if (_currSize < _maxSize) _currSize++;
_currIdx = NioUtils.PositiveMod((_currIdx + 1), _maxSize);
_data[_currIdx] = data;
}
///<summary>
/// Gets the element at index. The 0 element is the last one added.
///</summary>
public T GetElementAt(int index)
{
if (index >= _currSize)
{
throw new System.ArgumentException("Index out of bounds exception.", "index");
}
int shiftIndex = NioUtils.PositiveMod((_currIdx - index), _maxSize);
return _data[shiftIndex];
}
/// Implement interface IEnumerable in order to iterate throught this object.
public IEnumerator GetEnumerator()
{
int count = 0;
int index = _currIdx;
while (count < _currSize)
{
count++;
yield return _data[index];
index = NioUtils.PositiveMod((index - 1), _maxSize);
}
}
}
Where PositiveMod is:
public static int PositiveMod(int value, int n)
{
int v = value % n;
return v >= 0 ? v : n + v;
}
I have a server and I wan't each connection to be saved into a list. Lets say:
type Connection struct {
Id uint16
Conn *conn.TCP
}
var connections []Connection
But what I wanted to remove / fetch the specific connection id? What should I use?
I was thinking of something like:
func GetConnectionById(id uint16) Connection {
for k, v := range connections {
if v.Id == id {
return v
}
}
}
Is there a better approach?
Why not identify each Connection in a map by its Id?
package main
type Connection struct {
Id uint16
X string
}
var connections map[uint16]Connection
func main() {
connections = make(map[uint16]Connection)
connections[1] = Connection{}
}
in this program i have used different array variable for each of
the fields in a
database.In database all fields having the same datatype and now i want to store all
the fields values into one array variable.is it possible???
import java.sql.*;
class ja1
{
public static void main(String ar[])
{
try
{
int x,i,j,k,l;
int a[]=new int[30];
int b[]=new int[30];
int c[]=new int[30];
int d[]=new int[30];
int count[]=new int[10];
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection c1=DriverManager.getConnection("Jdbc:Odbc:ds");
Statement s=c1.createStatement();
ResultSet r=s.executeQuery("select * from pro");
i=0;
j=0;
k=0;
l=0;
x=0;
while(r.next())
{
a[i]=r.getInt(2);
i++;
b[j]=r.getInt(3);
j++;
c[k]=r.getInt(4);
k++;
d[l]=r.getInt(5);
l++;
}
for(i=0;i<6;i++)
System.out.println(""+a[i]);
for(j=0;j<6;j++)
System.out.println(""+b[j]);
System.out.print("\n\n");
for(k=0;k<6;k++)
System.out.println(""+c[k]);
System.out.print("\n\n");
for(l=0;l<6;l++)
System.out.println(""+d[l]);
}
catch(Exception e)
{
System.out.print(e);
}
}
}
Yes, it is possible in several ways :
1) If you want to use only one array then please create an array with size of 120 (4X30) and use 4 counter to arrange your data in range. That means, your first variable would be from index 0 to 29, the 2nd would be from 30 to 69 and so on. This is not good if you don't know the exact size of your array as you are binding them with perfect size of 30.
2) You can create a POJO and have 4 arrays into it, you can use a List instead of array, but it depends on your implementation. So, create a class, put 4 arrays into it, give good variable names and access thru getter/setter methods. This will be a clear code
3) You can use a Map<Integer,Integer[]> or Map<Integer,List<Integer>> and have a single variable/reference which is holding your key value pair.
It all depends on you, if you dont know, why are you using arrays,then please move the Collection
I would define a POJO for the record and then use a generic list to add and iterate the record/s
Try this:
class RecordData
{
public int First;
public int Second;
public int Third;
public int Fourth;
}
class ja1
{
public static void main(String ar[])
{
try
{
List<RecordData> list = new ArrayList<RecordData>;
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection c1=DriverManager.getConnection("Jdbc:Odbc:ds");
Statement s=c1.createStatement();
ResultSet r=s.executeQuery("select * from pro");
while(r.next())
{
RecordData data = new RecordData();
data.First = r.getInt(2);
data.Second = r.getInt(3);
data.Third = r.getInt(4);
data.Fourth = r.getInt(5);
list.add(data);
}
for(RecordData data : list) {
System.out.println(data.First);
System.out.println(data.Second);
System.out.println(data.Third);
System.out.println(data.Fourth);
}
}
catch(Exception e)
{
System.out.print(e);
}
}
}
I am trying to perform a rating system, where with the choices to select from returns a constant number so I can insert a value into a database. My intentions are to have 3 choices, 'Great', 'Mediocre' and 'Bad'. I would like Great to be a constant for '3', Mediocre to have a constant '2' and Bad to have a constant for '1'. I would like to insert only the numerical values if possible, any easy way to do this?
Anthony
The RadioGroup has the method getCheckedRadioButtonId() which returns the resource id of the selected RadioButton.
You could setup a switch case like:
private static final int CHOICE_GREAT = 3;
private static final int CHOICE_MEDIOCRE = 2;
private static final int CHOICE_BAD = 1;
int selected = getRating();
private int getRating() {
switch (ratingGroup.getCheckedRadioButtonId()) {
case R.id.RadioButtonGreat:
return CHOICE_GREAT;
case R.id.RadioButtonMediocre:
return CHOICE_MEDIOCRE;
case R.id.RadioButtonBad:
return CHOICE_BAD;
}
}