怎样获取SqLite请参考初识SqlLite ---.net连接数据库,怎样在SQLite使用Linq请参考在C#中利用Nuget包使用SQLite数据库和Linq to SQLite
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SQLite;
//using System.Windows.Forms; class Program
{ public static void Main()
{
SQLiteDatabase sqlite = new SQLiteDatabase(); sqlite.ExecuteNonQuery("create table datas(name text)");
sqlite.ExecuteNonQuery("insert into datas values('hello')");
DataTable dt = sqlite.GetDataTable("select * from datas");
Console.WriteLine(dt.Rows[][].ToString());
}
} class SQLiteDatabase
{
String dbConnection; /// <summary>
/// Default Constructor for SQLiteDatabase Class.
/// </summary>
public SQLiteDatabase()
{
dbConnection = "Data Source=recipes.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(, str.Length - );
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 >= )
{
foreach (KeyValuePair<String, String> val in data)
{
vals += String.Format(" {0} = '{1}',", val.Key.ToString(), val.Value.ToString());
}
vals = vals.Substring(, vals.Length - );
}
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)
{
Console.WriteLine(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(, columns.Length - );
values = values.Substring(, values.Length - );
try
{
this.ExecuteNonQuery(String.Format("insert into {0}({1}) values({2});", tableName, columns, values));
}
catch (Exception fail)
{
Console.WriteLine(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;
}
}
}