mardi 31 juillet 2012

Integrating a SQLite database in your c# application

Hello all,
I needed in one of my project to store data in a database, So as I only know Mysql I directly jump on it.
But my big problem was that I have to put all of the files in one package the thing that Mysql won't allow me to do, cause Mysql is a server database witch means that we can only connect to it and not integrate it in our application like this example . (correct me if I'm wrong please)
So I searched more and I found this little piece of jewellery System.data.sql.dll witch is a SQL based database direct link library that could be simply integrated in your C# application.
These are some tools I used to create and manage my database:
Some useful tutoriels:
using the sqlite function and send SQL queries. 
Gives a very useful class to manage data with dataGridView, inserting , updating and all those stuff
I added a method that can create data table:

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SQLite;
using System.Windows.Forms;

class SQLiteDatabase
{
    String dbConnection;

    /// <summary>
    ///     Default Constructor for SQLiteDatabase Class.
    /// </summary>
    public SQLiteDatabase()
    {
        dbConnection = "Data Source=REMOTES.s3db";
    }

    /// <summary>
    ///     Single Param Constructor for specifying the DB file.
    /// </summary>
    /// <param name="inputFile">The File containing the DB</param>
    public SQLiteDatabase(String inputFile)
    {
        dbConnection = String.Format("Data Source={0}", inputFile);
    }

    /// <summary>
    ///     Single Param Constructor for specifying advanced connection options.
    /// </summary>
    /// <param name="connectionOpts">A dictionary containing all desired options and their values</param>
    public SQLiteDatabase(Dictionary<String, String> connectionOpts)
    {
        String str = "";
        foreach (KeyValuePair<String, String> row in connectionOpts)
        {
            str += String.Format("{0}={1}; ", row.Key, row.Value);
        }
        str = str.Trim().Substring(0, str.Length - 1);
        dbConnection = str;
    }

    /// <summary>
    ///     Allows the programmer to run a query against the Database.
    /// </summary>
    /// <param name="sql">The SQL to run</param>
    /// <returns>A DataTable containing the result set.</returns>
    public DataTable GetDataTable(string sql)
    {
        DataTable dt = new DataTable();
        try
        {
            SQLiteConnection cnn = new SQLiteConnection(dbConnection);
            cnn.Open();
            SQLiteCommand mycommand = new SQLiteCommand(cnn);
            mycommand.CommandText = sql;
            SQLiteDataReader reader = mycommand.ExecuteReader();
            dt.Load(reader);
            reader.Close();
            cnn.Close();
        }
        catch (Exception e)
        {
            throw new Exception(e.Message);
        }
        return dt;
    }

    /// <summary>
    ///     Allows the programmer to interact with the database for purposes other than a query.
    /// </summary>
    /// <param name="sql">The SQL to be run.</param>
    /// <returns>An Integer containing the number of rows updated.</returns>
    public int ExecuteNonQuery(string sql)
    {
        SQLiteConnection cnn = new SQLiteConnection(dbConnection);
        cnn.Open();
        SQLiteCommand mycommand = new SQLiteCommand(cnn);
        mycommand.CommandText = sql;
        int rowsUpdated = mycommand.ExecuteNonQuery();
        cnn.Close();
        return rowsUpdated;
    }

    /// <summary>
    ///     Allows the programmer to retrieve single items from the DB.
    /// </summary>
    /// <param name="sql">The query to run.</param>
    /// <returns>A string.</returns>
    public string ExecuteScalar(string sql)
    {
        SQLiteConnection cnn = new SQLiteConnection(dbConnection);
        cnn.Open();
        SQLiteCommand mycommand = new SQLiteCommand(cnn);
        mycommand.CommandText = sql;
        object value = mycommand.ExecuteScalar();
        cnn.Close();
        if (value != null)
        {
            return value.ToString();
        }
        return "";
    }

    /// <summary>
    ///     Allows the programmer to easily update rows in the DB.
    /// </summary>
    /// <param name="tableName">The table to update.</param>
    /// <param name="data">A dictionary containing Column names and their new values.</param>
    /// <param name="where">The where clause for the update statement.</param>
    /// <returns>A boolean true or false to signify success or failure.</returns>
    public bool Update(String tableName, Dictionary<String, String> data, String where)
    {
        String vals = "";
        Boolean returnCode = true;
        if (data.Count >= 1)
        {
            foreach (KeyValuePair<String, String> val in data)
            {
                vals += String.Format(" {0} = '{1}',", val.Key.ToString(), val.Value.ToString());
            }
            vals = vals.Substring(0, vals.Length - 1);
        }
        try
        {
            this.ExecuteNonQuery(String.Format("update {0} set {1} where {2};", tableName, vals, where));
        }
        catch
        {
            returnCode = false;
        }
        return returnCode;
    }

    /// <summary>
    ///     Allows the programmer to easily delete rows from the DB.
    /// </summary>
    /// <param name="tableName">The table from which to delete.</param>
    /// <param name="where">The where clause for the delete.</param>
    /// <returns>A boolean true or false to signify success or failure.</returns>
    public bool Delete(String tableName, String where)
    {
        Boolean returnCode = true;
        try
        {
            this.ExecuteNonQuery(String.Format("delete from {0} where {1};", tableName, where));
        }
        catch (Exception fail)
        {
            MessageBox.Show(fail.Message);
            returnCode = false;
        }
        return returnCode;
    }

    /// <summary>
    ///     Allows the programmer to easily insert into the DB
    /// </summary>
    /// <param name="tableName">The table into which we insert the data.</param>
    /// <param name="data">A dictionary containing the column names and data for the insert.</param>
    /// <returns>A boolean true or false to signify success or failure.</returns>
    public bool Insert(String tableName, Dictionary<String, String> data)
    {
        String columns = "";
        String values = "";
        Boolean returnCode = true;
        foreach (KeyValuePair<String, String> val in data)
        {
            columns += String.Format(" {0},", val.Key.ToString());
            values += String.Format(" '{0}',", val.Value);
        }
        columns = columns.Substring(0, columns.Length - 1);
        values = values.Substring(0, values.Length - 1);
        try
        {
            this.ExecuteNonQuery(String.Format("insert into {0}({1}) values({2});", tableName, columns, values));
        }
        catch (Exception fail)
        {
            MessageBox.Show(fail.Message);
            returnCode = false;
        }
        return returnCode;
    }

    /// <summary>
    ///     Allows the programmer to easily delete all data from the DB.
    /// </summary>
    /// <returns>A boolean true or false to signify success or failure.</returns>
    public bool ClearDB()
    {
        DataTable tables;
        try
        {
            tables = this.GetDataTable("select NAME from SQLITE_MASTER where type='table' order by NAME;");
            foreach (DataRow table in tables.Rows)
            {
                this.ClearTable(table["NAME"].ToString());
            }
            return true;
        }
        catch
        {
            return false;
        }
    }

    /// <summary>
    ///     Allows the user to easily clear all data from a specific table.
    /// </summary>
    /// <param name="table">The name of the table to clear.</param>
    /// <returns>A boolean true or false to signify success or failure.</returns>
    public bool ClearTable(String table)
    {
        try
        {

            this.ExecuteNonQuery(String.Format("delete from {0};", table));
            return true;
        }
        catch
        {
            return false;
        }
    }
    public bool CreateTable(String TableName)
    {
        try
        {
            this.ExecuteNonQuery("CREATE TABLE IF NOT EXISTS " + TableName + " ( id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, name VARCHAR(100) NOT NULL);");
            return true;
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.ToString());
            return false;
        }
    }
}






vendredi 6 juillet 2012

Talking to an external EEPROM via I2C protocol

Hello,
you may want sometimes to save data that are too much to handle by your poor little pic, well you may thought of using an external eeprom to save all your data their,
In this tutoriel, I'm going to tell how to interface the 24LC256 eeprom with a 16F887 pic microcontroller.

I2C is a protocol that can allow multiple slaves and multiple masters to be connected in the same network, and that's pretty awsom ^^, most of the time there is only one master and many slaves, but in our case there will be one master (our PIC 16F887) and one slave our (24LC256 eeprom).
The master can communicate with only one slave at a time so how can he make a difference between his slaves?
well that's easy every slave has its unique address in the network for example our 24LC256 address has a 7 bit address that's equal to in binary 0B1010A1A2A3,
A master in a I2C network can read xor write it can't do both of them at the same time, so you may wonder how the slave would know if the master need to right or read from it,
well that's simple if the master want to write in the eeprom it sends 0XA0 and if it want to read it sends 0XA1, in other terms the LSB is the bit responsible for reading or writing.

wiring The 24LC256 EEPROM

A1 A2 and A3 are wired to the ground so our eeprom address is 0B1010000
Wp it's a bit for writing protection or read only, I'm not sur just wired to the ground.
SDA is the pin responsible for sending and receiving data,
SCK is the serial clock
We must use 2 pull up resistor for SDA and SCL (in proteus isis use the pull up resistor model)

Writing and reading from the EEPROM

we will store a data in a specific address then we are going to read data from that address.
unsigned char i = 0;
char txt[4];
void rc(){
     uart1_write(10);
     uarT1_write(13);
}
void main(){
  uart1_init(9600);
  I2C1_Init(100000);
  uart1_write_text("initialize I2C communication");rc();
  I2C1_Start();
  uart1_write_text("Start I2C communication");rc();
  I2C1_Wr(0xA0);
  delay_ms(10);
  uart1_write_text("write eeprom address");rc();
  I2C1_Wr(0x00);
  delay_ms(10);
  uart1_write_text("write low address");rc();
  I2C1_Wr(0x00);
   delay_ms(10);
   uart1_write_text("write high address");rc();
  I2C1_Wr(26); //donnée à écrire
  delay_ms(10);
  uart1_write_text("send to be stored");rc();
  I2C1_Stop();
  uart1_write_text("Stop I2C communication");rc();
  Delay_100ms();
  I2C1_Start();
  uart1_write_text("Start I2C communication");rc();
  I2C1_Wr(0xA0);
    delay_ms(10);
    uart1_write_text("write eeprom address");rc();
  I2C1_Wr(0x00);
     delay_ms(10);
     uart1_write_text("Start I2C communication");rc();
  I2C1_Wr(0X00);
  delay_ms(10);
  uart1_write_text("write low address");rc();
  I2C1_Repeated_Start();
  uart1_write_text("write high address");rc();
  I2C1_Wr(0xA1);
  delay_ms(10);
  uart1_write_text("read eeprom address");rc();
  i=I2C1_Rd(0);
  uart1_write_text("read stored data");rc();
  I2C1_Stop();
  uart1_write_text("Stop I2C communication");rc();
  bytetostr(i,txt);
  uart1_write_text(txt);rc();
}

I hope that was clear, don't stop sharing!!