SQLITE在ASP.NET中的应用
在asp.net web 程序中使用Sqlite数据库 本文介绍了如何在asp.net web 程序中使用Sqlite嵌入式数据库，sqlite数据库可以作为文件放在站点的APP_DATA目录下，适合小网站使用，使用它不需要买sql server空间，而且据说它的性能很不错。
Sqlite是嵌入数据库，类似与MS Sql Server Compact，之所以不用Sql server compact是因为它既不支持SELECT TOP也不支持ROW_NUMBER()还不支持LIMIT，也就是我没有办法用它分页了，取数据的时候必须根据条件取，不能在给定条件下取n条。
1. 安装Sqlite数据库，sqlite数据库非常方便，他的安装只有一个exe文件，可以下载。
下载可执行文件之后使用命令“sqlite3 dbname”执行就可以创建数据库。
或者为了开发方便下载Sqlite Developer软件，使用软件创建也有方便。下载链接
2. 安装dot net下的Sqlite数据库驱动，其实就是一个dll，System.Data.SQLite,他是一个开源项目，可以到SourceForge上下载
3. 在VS中建立一个Web Application，并引用2中的dll
4. 在default.aspx的cs文件中实现访问Sqlite的代码，代码和注释如下：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SQLite;
namespace SqliteWebApp
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//这个文件是预先生成的数据库文件
string sqliteFilePath = Server.MapPath("~/App_Data/firstsqlite.db");
DataSet ds = new DataSet();
//声明一个Sqlite数据库的链接
using (SQLiteConnection conn = new SQLiteConnection("Data Source=" + sqliteFilePath))
{
//创建sqlite命令
using (SQLiteCommand comm = conn.CreateCommand())
{
//打开数据库链接
conn.Open();
//插入数据
comm.CommandText = "INSERT INTO [t] VALUES(10,'Hello 9')";
comm.ExecuteNonQuery();
//更新数据
comm.CommandText = "UPDATE [t] SET name = 'Hello 10' WHERE id = 10";
comm.ExecuteNonQuery();
//使用参数插入数据
comm.CommandText = "INSERT INTO [t] VALUES(@id,@name)";
comm.Parameters.AddRange(
new SQLiteParameter[]{
CreateSqliteParameter("@id",DbType.Int32,4,11),
CreateSqliteParameter("@name",DbType.String,10,"Hello 11")
});
comm.ExecuteNonQuery();
comm.Parameters.Clear();
//select数据分页用limit就行，很方便
comm.CommandText = "Select * From MAIN.[t]";
using (SQLiteDataAdapter adapter = new SQLiteDataAdapter(comm))
{
adapter.Fill(ds);
}
}
}
gv1.DataSource = ds;
gv1.DataBind();
}
/**////
/// 放回一个SQLiteParameter
///
/// 参数名字
/// 参数类型
/// 参数大小
/// 参数值
///SQLiteParameter的值
static private SQLiteParameter CreateSqliteParameter(string name,DbType type,int size,object value)
{
SQLiteParameter parm = new SQLiteParameter(name,type, size);
parm.Value = value;
return parm;
}
}
}
最后希望的MS Sql Server Compact可以做一些改进，让我们可以舒服的使用。
1. DLL下载地址
http://system.data.sqlite.org/index.html/doc/trunk/www/downloads.wiki
2. Add Reference System.Data.SQLite.dll
using System.Data.SQLite
把SQLite.Interop.dll放到可执行文件的相同目录下
3. 代码
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[0][0].ToString());
}
}
class SQLiteDatabase
{
String dbConnection;
///
/// Default Constructor for SQLiteDatabase Class.
///
public SQLiteDatabase()
{
dbConnection = "Data Source=recipes.s3db";
}
///
/// Single Param Constructor for specifying the DB file.
///
/// The File containing the DB
public SQLiteDatabase(String inputFile)
{
dbConnection = String.Format("Data Source={0}", inputFile);
}
///
/// Single Param Constructor for specifying advanced connection options.
///
/// A dictionary containing all desired options and their values
public SQLiteDatabase(Dictionary connectionOpts)
{
String str = "";
foreach (KeyValuePair row in connectionOpts)
{
str += String.Format("{0}={1}; ", row.Key, row.Value);
}
str = str.Trim().Substring(0, str.Length - 1);
dbConnection = str;
}
///
/// Allows the programmer to run a query against the Database.
///
/// The SQL to run
///A DataTable containing the result set.
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;
}
///
/// Allows the programmer to interact with the database for purposes other than a query.
///
/// The SQL to be run.
///An Integer containing the number of rows updated.
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;
}
///
/// Allows the programmer to retrieve single items from the DB.
///
/// The query to run.
///A string.
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 "";
}
///
/// Allows the programmer to easily update rows in the DB.
///
/// The table to update.
/// A dictionary containing Column names and their new values.
/// The where clause for the update statement.
///A boolean true or false to signify success or failure.
public bool Update(String tableName, Dictionary data, String where)
{
String vals = "";
Boolean returnCode = true;
if (data.Count >= 1)
{
foreach (KeyValuePair 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;
}
///
/// Allows the programmer to easily delete rows from the DB.
///
/// The table from which to delete.
/// The where clause for the delete.
///A boolean true or false to signify success or failure.
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;
}
///
/// Allows the programmer to easily insert into the DB
///
/// The table into which we insert the data.
/// A dictionary containing the column names and data for the insert.
///A boolean true or false to signify success or failure.
public bool Insert(String tableName, Dictionary data)
{
String columns = "";
String values = "";
Boolean returnCode = true;
foreach (KeyValuePair 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)
{
Console.WriteLine(fail.Message);
returnCode = false;
}
return returnCode;
}
///
/// Allows the programmer to easily delete all data from the DB.
///
///A boolean true or false to signify success or failure.
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;
}
}
///
/// Allows the user to easily clear all data from a specific table.
///
/// The name of the table to clear.
///A boolean true or false to signify success or failure.
public bool ClearTable(String table)
{
try
{
this.ExecuteNonQuery(String.Format("delete from {0};", table));
return true;
}
catch
{
return false;
}
}
}
Sqlite是嵌入数据库，类似与MS Sql Server Compact，之所以不用Sql server compact是因为它既不支持SELECT TOP也不支持ROW_NUMBER()还不支持LIMIT，也就是我没有办法用它分页了，取数据的时候必须根据条件取，不能在给定条件下取n条。
1. 安装Sqlite数据库，sqlite数据库非常方便，他的安装只有一个exe文件，可以下载。
下载可执行文件之后使用命令“sqlite3 dbname”执行就可以创建数据库。
或者为了开发方便下载Sqlite Developer软件，使用软件创建也有方便。下载链接
2. 安装dot net下的Sqlite数据库驱动，其实就是一个dll，System.Data.SQLite,他是一个开源项目，可以到SourceForge上下载
3. 在VS中建立一个Web Application，并引用2中的dll
4. 在default.aspx的cs文件中实现访问Sqlite的代码，代码和注释如下：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SQLite;
namespace SqliteWebApp
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//这个文件是预先生成的数据库文件
string sqliteFilePath = Server.MapPath("~/App_Data/firstsqlite.db");
DataSet ds = new DataSet();
//声明一个Sqlite数据库的链接
using (SQLiteConnection conn = new SQLiteConnection("Data Source=" + sqliteFilePath))
{
//创建sqlite命令
using (SQLiteCommand comm = conn.CreateCommand())
{
//打开数据库链接
conn.Open();
//插入数据
comm.CommandText = "INSERT INTO [t] VALUES(10,'Hello 9')";
comm.ExecuteNonQuery();
//更新数据
comm.CommandText = "UPDATE [t] SET name = 'Hello 10' WHERE id = 10";
comm.ExecuteNonQuery();
//使用参数插入数据
comm.CommandText = "INSERT INTO [t] VALUES(@id,@name)";
comm.Parameters.AddRange(
new SQLiteParameter[]{
CreateSqliteParameter("@id",DbType.Int32,4,11),
CreateSqliteParameter("@name",DbType.String,10,"Hello 11")
});
comm.ExecuteNonQuery();
comm.Parameters.Clear();
//select数据分页用limit就行，很方便
comm.CommandText = "Select * From MAIN.[t]";
using (SQLiteDataAdapter adapter = new SQLiteDataAdapter(comm))
{
adapter.Fill(ds);
}
}
}
gv1.DataSource = ds;
gv1.DataBind();
}
/**////
/// 放回一个SQLiteParameter
///
/// 参数名字
/// 参数类型
/// 参数大小
/// 参数值
///
static private SQLiteParameter CreateSqliteParameter(string name,DbType type,int size,object value)
{
SQLiteParameter parm = new SQLiteParameter(name,type, size);
parm.Value = value;
return parm;
}
}
}
最后希望的MS Sql Server Compact可以做一些改进，让我们可以舒服的使用。
1. DLL下载地址
http://system.data.sqlite.org/index.html/doc/trunk/www/downloads.wiki
2. Add Reference System.Data.SQLite.dll
using System.Data.SQLite
把SQLite.Interop.dll放到可执行文件的相同目录下
3. 代码
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[0][0].ToString());
}
}
class SQLiteDatabase
{
String dbConnection;
///
/// Default Constructor for SQLiteDatabase Class.
///
public SQLiteDatabase()
{
dbConnection = "Data Source=recipes.s3db";
}
///
/// Single Param Constructor for specifying the DB file.
///
/// The File containing the DB
public SQLiteDatabase(String inputFile)
{
dbConnection = String.Format("Data Source={0}", inputFile);
}
///
/// Single Param Constructor for specifying advanced connection options.
///
/// A dictionary containing all desired options and their values
public SQLiteDatabase(Dictionary
{
String str = "";
foreach (KeyValuePair
{
str += String.Format("{0}={1}; ", row.Key, row.Value);
}
str = str.Trim().Substring(0, str.Length - 1);
dbConnection = str;
}
///
/// Allows the programmer to run a query against the Database.
///
/// The SQL to run
///
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;
}
///
/// Allows the programmer to interact with the database for purposes other than a query.
///
/// The SQL to be run.
///
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;
}
///
/// Allows the programmer to retrieve single items from the DB.
///
/// The query to run.
///
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 "";
}
///
/// Allows the programmer to easily update rows in the DB.
///
/// The table to update.
/// A dictionary containing Column names and their new values.
/// The where clause for the update statement.
///
public bool Update(String tableName, Dictionary
{
String vals = "";
Boolean returnCode = true;
if (data.Count >= 1)
{
foreach (KeyValuePair
{
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;
}
///
/// Allows the programmer to easily delete rows from the DB.
///
/// The table from which to delete.
/// The where clause for the delete.
///
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;
}
///
/// Allows the programmer to easily insert into the DB
///
/// The table into which we insert the data.
/// A dictionary containing the column names and data for the insert.
///
public bool Insert(String tableName, Dictionary
{
String columns = "";
String values = "";
Boolean returnCode = true;
foreach (KeyValuePair
{
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)
{
Console.WriteLine(fail.Message);
returnCode = false;
}
return returnCode;
}
///
/// Allows the programmer to easily delete all data from the DB.
///
///
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;
}
}
///
/// Allows the user to easily clear all data from a specific table.
///
/// The name of the table to clear.
///
public bool ClearTable(String table)
{
try
{
this.ExecuteNonQuery(String.Format("delete from {0};", table));
return true;
}
catch
{
return false;
}
}
}