I've just started working on a Database application and maintaining a previous developer's code, one thing I see is that column and table names are hardcoded throughout the code which is something I'd like to avoid. To me it seems like a practice that is prone to spelling mistakes reaping havoc across the application.
Some I've looked at include:
Constant strings
const string TableName_ColumnName = "TestName";
Dictionary and Enum:
public static string GetColumnName(ColumnId inColId)
{
[Code]....
I think I prefer the second option but it means that retrieving the column names means quite a long winded function call.
I have .db3 file, and he has 14 tables,and every table has certain number of columns. Example i have table called "BASIC_INFO" and that table has columns "First Name", "Last Name" and "Age".
How can i get name of table and name of every column,so if i some day add column "Male" i get name of this column too. I need first to calculate number of columns,put that in some integer, and then for example create string array which will contain : array[0] = "First Name" ,array[1] = "Last Name"...
SQLiteConnection myConn = new SQLiteConnection("Data Source=" + DB3Path + ";Version=3;New=False;Compress=True;"); //string query = "Select * From " + DB3Path + ".INFORMATION_SCHEMA.COLUMNS"; string query = "Select * From BASIC_INFO.INFORMATION_SCHEMA.COLUMNS;"; SQLiteCommand sqCommand = new SQLiteCommand(query);
[Code] ....
I tried this too:
string query = "select * from INFORMATION_SCHEMA.COLUMNS" + "where TABLE_Name='BASIC_INFO'" + "order by ORDINAL_POSITION;"; string query = "SELECT TOP 0 * FROM BASIC_INFO";
I am writing a code in which i need to grab a column from a variety of tables. So basically there are 10 tables in which they hey have the same columns inside of them (Submitted and Amount). I need to grab the amount column from all the tables. What would be the c# sql command for that.
I tryed to create program I wich u can guess number, I made some if to prevent inputting 2 times the same number It works. I tryed to apply the same process for generating
I have made the following code to illustrate my problem:
#pragma once #include <bitset> #include <iostream>
[Code].....
Now I want to avoid my bitset field being constructed before the ConstructTest constructor is called. So at first I tried wrapping it in a unique_ptr but found out that this would give me some potential problems with const functions.
And then I realized I could just set it to NULL, as I have in the above code. I tried that, got unexpected print outs, until I found out that NULL is just equal to 0 in C++ and that the bitset has a = operator that takes a number, int, long or maybe something else. Either way, this effectively constructs the bitset and sets it to the number 0.
So my efforts so far have been shut down. But then how can I avoid the bitset being constructed in advance, if at all possible?
how to handle reallocation costs when input data is unbounded.
For instance, in a low-latency environment such as a trading platform or real-time data collection system or MMORPG where you can receive a large amount of input, you can not afford a stall while the data structure is rebuilt with a larger buffer. You can use historical data to "guess" an appropriate size but this is far from fool-proof. You can also create a sentinel thread that monitors the load factor of your data structure but that brings its own problems (e.g. another thread that needs execution time and to lock the data).
i have a vector of stores. i would like to delete the specified choice(store) from the list. Here is what i have but my erase statement is wrong and wont compile.
void Store::deleteSpecifiedStoreFromList(string choice) { for (int i = 0; i < this->stores.size(); i++) { if(this->stores[i].getStoreNames() == choice) { this->stores.erase( std::remove_if( this->stores.begin(), this->stores.end(), choice ), this->stores.end() ); } } }
I am having an issue with my sort function. This is one part of the Hash table program. The main issue is that I am trying to sort the pointer table after all of the values have been entered. The ptr_sort function is not a class function and so I am therefore unable to use the class variables psize and pTable. Is there another way I should be trying this? it is a Vector should I use the sort() function from the vector class in STL?
If a user enters a string of boolean algebra it will ouput the table.
I have input parsing, cycling through the combinations, and outputing working. However once i parse the input I am not sure what to do with it. I have thought of having it write the parsed input to a new file as a function and then use that function, but that seems bad.
How to dynamically create the function, how to implement it.
BTW This is a console function, if that changes anything.
1) Count the number of rows in the table booking that are open and where the booking.postcode is "MK",
2) Take a note of the plot (in booking.plot_id), and then update the table plot.jobs with the value count.
For example running the SQL query when booking table has the following rows:
Would see the following highlighted values in plot.jobs being updated to 1:
I managed to resolve it with this code so far (note I am using Connector/Net):
public void RefreshPlot(){ string query = "SELECT Count(*) AS count, plot_id FROM booking WHERE postcode='MK' AND status='open' GROUP BY plot_id"; var cmd = new MySqlCommand(query, _connection); var da = new MySqlDataAdapter(cmd); var dtCounts = new DataTable(); da.Fill(dtCounts);
[code]....
Currently, my code only checks for existing rows in the booking table and updates the plot table. However if the row gets deleted in the booking, then the changes are not reflected in the plot table.
Example: If we delete the row with plot.id=1 and plot.plot_id=4, then booking.plot_id should go back to being 0, if it was initially 1. At the moment, it doesn't. How would I update my SQL statement to better reflect this? In a sense, it should check for "non-existent" rows, i.e. the impact that the row plot.plot_id=4 & plot.id=1 has on booking.plot_id when deleted?
I have a C# .NET Application which get data from QuickBooks via the ODBC Driver and save the result to C# data table. So, I want to transfer this data table to a mysql table on my own server. That's the code I use:
using System.IO; using MySql.Data.MySqlClient; //Add mysql dll on the .NET Tab in Project's references string connStr = "DSN=QBTest;"; string myServerAddress = "192.168.0.243"; string myDataBase = "CostTest";
Suppose I want to represent an apartment building in terms of floors and rooms with a single data object. Each floor has the same number of rooms at any given time. During the course of the program, I will need to change the number of floors occasionally and will need to change the number of rooms on each floor occasionally. (Don't worry about the building permits needed to do this.) Now, I also want to be able to iterate over either each floor (think "row") or each room (think "column"). For example, I might want to program the equivalent of "Johnson, go fix all the front doors on the 8th floor" or the equivalent of "Johnson, go fix all the front doors to room B on each floor". (Yeah, I know, for the latter I could iterate over each floor and then access room B but that doesn't feel as "clean" as being able to iterate over a separate room/column.)
Suppose I want to represent an apartment building in terms of floors and rooms with a single data object. Each floor has the same number of rooms at any given time. During the course of the program, I will need to change the number of floors occasionally and will need to change the number of rooms on each floor occasionally. (Don't worry about the building permits needed to do this.)
Now, I also want to be able to iterate over either each floor (think "row") or each room (think "column"). For example, I might want to program the equivalent of "Johnson, go fix all the front doors on the 8th floor" or the equivalent of "Johnson, go fix all the front doors to room B on each floor". (Yeah, I know, for the latter I could iterate over each floor and then access room B but that doesn't feel as "clean" as being able to iterate over a separate room/column.)
I have a 2d array where I manage donations and requests for different foods. I output a menu to the user who picks the options to either make a donation, make a request, fulfill a request, or print a status report of all the donations and requests. What I'm having trouble with is the fulfilling requests option. When the user picks fulfill requests that means that the donations are supposed to be subtracted from the requests. For example if there are 10 donations for grains and 15 requests for grains then after picking fulfill request there should be 0 donations for grains and 5 requests for grains but I don't know how to make the program do that since the values are in a 5 row by 2 column array. The five rows correspond to the five foods and the two columns correspond to donations and requests, respectively. Here's my code so far. Just disregard everything but the third case.
Code: #include <stdio.h>int main(){ int foodbank[5][2]= { {0,0}, {0,0},
i have a matrix containing a lot of points and each point has its coordinates x and y. That is a nx2 size array. I want to sort it according to the first column ascending, with x coordinates. For points that have the same x coord i would like to sort according to y coord. Here is what i did and i cannot get a good result.
Code:
#include <stdio.h> #include <stdlib.h> int main(){ int a[5][2] = {{1,0}, {4,2}, {2,4}, {8,6},{4,8}}; int temp=0; int i=0; int j=0;
I'm using GCC 4.8.1 and I want to implement a XML parser using TinyXML and port it to AngelScript
Now, it says: reference to 'Column' is ambiguous
I've declared a class called xml_parser and I've added everything of tinyxml as it's public member when I call Column(), and also Row(), it give's this error. what should I do?
Can i set each column in Gridview with different Datasource ? for example I create Gridview with 3 column , can I set each column with different datasource ?
