在C#中使用Sqlite增加对transaction支持
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SQLite;
using System.Globalization;
using System.Linq;
using System.Windows.Forms;
namespace Simple_Disk_Catalog
{
public class SQLiteDatabase
{
String DBConnection;
private readonly SQLiteTransaction _sqLiteTransaction;
private readonly SQLiteConnection _sqLiteConnection;
private readonly bool _transaction;
/// <summary>
/// Default Constructor for SQLiteDatabase Class.
/// </summary>
/// <param name="transaction">Allow programmers to insert,update and delete values in one transaction</param>
public SQLiteDatabase(bool transaction = false)
{
_transaction = transaction;
DBConnection = "Data Source=recipes.s3db";
if (transaction)
{
_sqLiteConnection = new SQLiteConnection(DBConnection);
_sqLiteConnection.Open();
_sqLiteTransaction = _sqLiteConnection.BeginTransaction();
}
}
/// <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>
/// Commit transaction to the database.
/// </summary>
public void CommitTransaction()
{
_sqLiteTransaction.Commit();
_sqLiteTransaction.Dispose();
_sqLiteConnection.Close();
_sqLiteConnection.Dispose();
}
/// <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 = connectionOpts.Aggregate("",(current,row) => current + String.Format("{0}={1}; ",row.Key,row.Value));
str = str.Trim().Substring(0,str.Length - 1);
DBConnection = str;
}
/// <summary>
/// Allows the programmer to create new database file.
/// </summary>
/// <param name="filePath">Full path of a new database file.</param>
/// <returns>true or false to represent success or failure.</returns>
public static bool CreateDB(string filePath)
{
try
{
SQLiteConnection.CreateFile(filePath);
return true;
}
catch (Exception e)
{
MessageBox.Show(e.Message,e.GetType().ToString(),MessageBoxButtons.OK,MessageBoxIcon.Error);
return false;
}
}
/// <summary>
/// Allows the programmer to run a query against the Database.
/// </summary>
/// <param name="sql">The SQL to run</param>
/// <param name="allowDBNullColumns">Allow null value for columns in this collection.</param>
/// <returns>A DataTable containing the result set.</returns>
public DataTable GetDataTable(string sql,IEnumerable<string> allowDBNullColumns = null)
{
var dt = new DataTable();
if (allowDBNullColumns != null)
foreach (var s in allowDBNullColumns)
{
dt.Columns.Add(s);
dt.Columns[s].AllowDBNull = true;
}
try
{
var cnn = new SQLiteConnection(DBConnection);
cnn.Open();
var mycommand = new SQLiteCommand(cnn) {CommandText = sql};
var reader = mycommand.ExecuteReader();
dt.Load(reader);
reader.Close();
cnn.Close();
}
catch (Exception e)
{
throw new Exception(e.Message);
}
return dt;
}
public string RetrieveOriginal(string value)
{
return
value.Replace("&","&").Replace("<","<").Replace(">","<").Replace(""","\"").Replace(
"'","'");
}
/// <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)
{
if (!_transaction)
{
var cnn = new SQLiteConnection(DBConnection);
cnn.Open();
var mycommand = new SQLiteCommand(cnn) {CommandText = sql};
var rowsUpdated = mycommand.ExecuteNonQuery();
cnn.Close();
return rowsUpdated;
}
else
{
var mycommand = new SQLiteCommand(_sqLiteConnection) { CommandText = sql };
return mycommand.ExecuteNonQuery();
}
}
/// <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)
{
if (!_transaction)
{
var cnn = new SQLiteConnection(DBConnection);
cnn.Open();
var mycommand = new SQLiteCommand(cnn) {CommandText = sql};
var value = mycommand.ExecuteScalar();
cnn.Close();
return value != null ? value.ToString() : "";
}
else
{
var sqLiteCommand = new SQLiteCommand(_sqLiteConnection) { CommandText = sql };
var value = sqLiteCommand.ExecuteScalar();
return value != null ? value.ToString() : "";
}
}
/// <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)
{
vals = data.Aggregate(vals,val) => current + String.Format(" {0} = '{1}',",val.Key.ToString(CultureInfo.InvariantCulture),val.Value.ToString(CultureInfo.InvariantCulture)));
vals = vals.Substring(0,vals.Length - 1);
}
try
{
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
{
ExecuteNonQuery(String.Format("delete from {0} where {1};",where));
}
catch (Exception fail)
{
MessageBox.Show(fail.Message,fail.GetType().ToString(),MessageBoxIcon.Error);
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>returns last inserted row id if it's value is zero than it means failure.</returns>
public long Insert(String tableName,String> data)
{
String columns = "";
String values = "";
String value;
foreach (KeyValuePair<String,String> val in data)
{
columns += String.Format(" {0},val.Key.ToString(CultureInfo.InvariantCulture));
values += String.Format(" '{0}',val.Value);
}
columns = columns.Substring(0,columns.Length - 1);
values = values.Substring(0,values.Length - 1);
try
{
if (!_transaction)
{
var cnn = new SQLiteConnection(DBConnection);
cnn.Open();
var sqLiteCommand = new SQLiteCommand(cnn)
{
CommandText =
String.Format("insert into {0}({1}) values({2});",columns,values)
};
sqLiteCommand.ExecuteNonQuery();
sqLiteCommand = new SQLiteCommand(cnn) { CommandText = "SELECT last_insert_rowid()" };
value = sqLiteCommand.ExecuteScalar().ToString();
}
else
{
ExecuteNonQuery(String.Format("insert into {0}({1}) values({2});",values));
value = ExecuteScalar("SELECT last_insert_rowid()");
}
}
catch (Exception fail)
{
MessageBox.Show(fail.Message,MessageBoxIcon.Error);
return 0;
}
return long.Parse(value);
}
/// <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()
{
try
{
var tables = GetDataTable("select NAME from SQLITE_MASTER where type='table' order by NAME;");
foreach (DataRow table in tables.Rows)
{
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
{
ExecuteNonQuery(String.Format("delete from {0};",table));
return true;
}
catch
{
return false;
}
}
/// <summary>
/// Allows the user to easily reduce size of database.
/// </summary>
/// <returns>A boolean true or false to signify success or failure.</returns>
public bool CompactDB()
{
try
{
ExecuteNonQuery("Vacuum;");
return true;
}
catch (Exception)
{
return false;
}
}
}
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