1、定义sqlite数据库存放位置的全局变量
public static string dataBaseFileName = AppDomain.CurrentDomain.BaseDirectory + "数据库名称.db";
public static string connectionString = @"Data Source=" + dataBaseFileName + "; Pooling=true;FailIfMissing=false;";
2、判断存放位置下是否存在数据库以及相关表
public static void ExistsDataBase()
{
if (!File.Exists(dataBaseFileName))
{
SQLiteConnection.CreateFile(dataBaseFileName);
}
if (!ExixtsTable("PointManage"))
{
ExecuteSql(@"CREATE TABLE PointManage(
Id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
PointAddress TEXT NOT NULL,
PointDes TEXT NOT NULL
)");
}
if (!ExixtsTable("PointValue"))
{
ExecuteSql(@"CREATE TABLE PointValue(
Id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
PointAddress TEXT NOT NULL,
Time TEXT NOT NULL,
Value NUMERIC NOT NULL
)");
ExecuteSql("CREATE INDEX PointAddress ON PointValue(PointAddress COLLATE BINARY ASC)");
ExecuteSql("CREATE INDEX Time ON PointValue(Time COLLATE BINARY ASC)");
}
}
3、完整代码
using System;
using System.Collections;
using System.Data.Common;
using System.Data;
using System.Data.SQLite;
using System.IO;
namespace PointChartsMonitoring.Util
{
public class DBHelperSQLite
{
public static string dataBaseFileName = AppDomain.CurrentDomain.BaseDirectory + "PointDataSources.db";
public static string connectionString = @"Data Source=" + dataBaseFileName + "; Pooling=true;FailIfMissing=false;";
public DBHelperSQLite()
{
}
public static void ExistsDataBase()
{
if (!File.Exists(dataBaseFileName))
{
SQLiteConnection.CreateFile(dataBaseFileName);
}
if (!ExixtsTable("PointManage"))
{
ExecuteSql(@"CREATE TABLE PointManage(
Id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
PointAddress TEXT NOT NULL,
PointDes TEXT NOT NULL
)");
}
if (!ExixtsTable("PointValue"))
{
ExecuteSql(@"CREATE TABLE PointValue(
Id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
PointAddress TEXT NOT NULL,
Time TEXT NOT NULL,
Value NUMERIC NOT NULL
)");
ExecuteSql("CREATE INDEX PointAddress ON PointValue(PointAddress COLLATE BINARY ASC)");
ExecuteSql("CREATE INDEX Time ON PointValue(Time COLLATE BINARY ASC)");
}
}
#region 公用方法
public static bool ExixtsTable(string tableName)
{
string sqlStr = $"SELECT count(*) from sqlite_master where type='table' and name='{
tableName}'";
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand(sqlStr, connection))
{
try
{
connection.Open();
return !(cmd.ExecuteScalar().ParseToInt() == 0);//不存在此表，返回false
}
catch (SQLiteException E)
{
connection.Close();
throw new Exception(E.Message);
}
}
}
}
public static int GetMaxID(string FieldName, string TableName)
{
string strsql = "select max(" + FieldName + ")+1 from " + TableName;
object obj = GetSingle(strsql);
if (obj == null)
{
return 1;
}
else
{
return int.Parse(obj.ToString());
}
}
public static bool Exists(string strSql)
{
object obj = GetSingle(strSql);
int cmdresult;
if (Equals(obj, null) || Equals(obj, DBNull.Value))
{
cmdresult = 0;
}
else
{
cmdresult = int.Parse(obj.ToString());
}
if (cmdresult == 0)
{
return false;
}
else
{
return true;
}
}
public static bool Exists(string strSql, params SQLiteParameter[] cmdParms)
{
object obj = GetSingle(strSql, cmdParms);
int cmdresult;
if (Equals(obj, null) || Equals(obj, DBNull.Value))
{
cmdresult = 0;
}
else
{
cmdresult = int.Parse(obj.ToString());
}
if (cmdresult == 0)
{
return false;
}
else
{
return true;
}
}
#endregion
#region 执行简单SQL语句
/// <summary>
/// 对SQLite数据库执行增删改操作，返回受影响的行数。
/// </summary>
/// <param name="sql">要执行的增删改的SQL语句</param>
/// <param name="parameters">执行增删改语句所需要的参数，参数必须以它们在SQL语句中的顺序为准</param>
/// <returns></returns>
public static int ExecuteNonQuery(string sql, SQLiteParameter[] parameters)
{
int affectedRows = 0;
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
connection.Open();
using (DbTransaction transaction = connection.BeginTransaction())
{
using (SQLiteCommand command = new SQLiteCommand(connection))
{
command.CommandText = sql;
if (parameters != null)
{
command.Parameters.AddRange(parameters);
}
affectedRows = command.ExecuteNonQuery();
}
transaction.Commit();
}
}
return affectedRows;
}
/// <summary>
/// 执行SQL语句，返回影响的记录数
/// </summary>
/// <param name="SQLString">SQL语句</param>
/// <returns>影响的记录数</returns>
public static int ExecuteSql(string SQLString)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand(SQLString, connection))
{
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (SQLiteException E)
{
connection.Close();
throw new Exception(E.Message);
}
}
}
}
/// <summary>
/// 执行多条SQL语句，实现数据库事务。
/// </summary>
/// <param name="SQLStringList">多条SQL语句</param>
public static void ExecuteSqlTran(ArrayList SQLStringList)
{
using (SQLiteConnection conn = new SQLiteConnection(connectionString))
{
conn.Open();
SQLiteCommand cmd = new SQLiteCommand();
cmd.Connection = conn;
SQLiteTransaction tx = conn.BeginTransaction();
cmd.Transaction = tx;
try
{
for (int n = 0; n < SQLStringList.Count; n++)
{
string strsql = SQLStringList[n].ToString();
if (strsql.Trim().Length > 1)
{
cmd.CommandText = strsql;
cmd.ExecuteNonQuery();
}
}
tx.Commit();
}
catch (SQLiteException E)
{
tx.Rollback();
throw new Exception(E.Message);
}
}
}
/// <summary>
/// 执行带一个存储过程参数的的SQL语句。
/// </summary>
/// <param name="SQLString">SQL语句</param>
/// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
/// <returns>影响的记录数</returns>
public static int ExecuteSql(string SQLString, string content)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
SQLiteCommand cmd = new SQLiteCommand(SQLString, connection);
SQLiteParameter myParameter = new SQLiteParameter("@content", DbType.String);
myParameter.Value = content;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (SQLiteException E)
{
throw new Exception(E.Message);
}
finally
{
cmd.Dispose();
connection.Close();
}
}
}
/// <summary>
/// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
/// </summary>
/// <param name="strSQL">SQL语句</param>
/// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
/// <returns>影响的记录数</returns>
public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
SQLiteCommand cmd = new SQLiteCommand(strSQL, connection);
SQLiteParameter myParameter = new SQLiteParameter("@fs", DbType.Binary);
myParameter.Value = fs;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (SQLiteException E)
{
throw new Exception(E.Message);
}
finally
{
cmd.Dispose();
connection.Close();
}
}
}
/// <summary>
/// 执行一条计算查询结果语句，返回查询结果（object）。
/// </summary>
/// <param name="SQLString">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public static object GetSingle(string SQLString)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand(SQLString, connection))
{
try
{
connection.Open();
object obj = cmd.ExecuteScalar();
if (Equals(obj, null) || Equals(obj, DBNull.Value))
{
return null;
}
else
{
return obj;
}
}
catch (SQLiteException e)
{
connection.Close();
throw new Exception(e.Message);
}
}
}
}
/// <summary>
/// 执行查询语句，返回SQLiteDataReader
/// </summary>
/// <param name="strSQL">查询语句</param>
/// <returns>SQLiteDataReader</returns>
public static SQLiteDataReader ExecuteReader(string strSQL)
{
SQLiteConnection connection = new SQLiteConnection(connectionString);
SQLiteCommand cmd = new SQLiteCommand(strSQL, connection);
try
{
connection.Open();
SQLiteDataReader myReader = cmd.ExecuteReader();
return myReader;
}
catch (SQLiteException e)
{
throw new Exception(e.Message);
}
}
/// <summary>
/// 执行查询语句，返回DataSet
/// </summary>
/// <param name="SQLString">查询语句</param>
/// <returns>DataSet</returns>
public static DataSet Query(string SQLString)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
DataSet ds = new DataSet();
try
{
connection.Open();
SQLiteDataAdapter command = new SQLiteDataAdapter(SQLString, connection);
command.Fill(ds, "ds");
}
catch (SQLiteException ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}
#endregion
#region 执行带参数的SQL语句
/// <summary>
/// 执行SQL语句，返回影响的记录数
/// </summary>
/// <param name="SQLString">SQL语句</param>
/// <returns>影响的记录数</returns>
public static int ExecuteSql(string SQLString, params SQLiteParameter[] cmdParms)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand())
{
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
int rows = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return rows;
}
catch (SQLiteException E)
{
throw new Exception(E.Message);
}
}
}
}
/// <summary>
/// 执行多条SQL语句，实现数据库事务。
/// </summary>
/// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的SQLiteParameter[]）</param>
public static void ExecuteSqlTran(Hashtable SQLStringList)
{
using (SQLiteConnection conn = new SQLiteConnection(connectionString))
{
conn.Open();
using (SQLiteTransaction trans = conn.BeginTransaction())
{
SQLiteCommand cmd = new SQLiteCommand();
try
{
//循环
foreach (DictionaryEntry myDE in SQLStringList)
{
string cmdText = myDE.Key.ToString();
SQLiteParameter[] cmdParms = (SQLiteParameter[])myDE.Value;
PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
trans.Commit();
}
}
catch
{
trans.Rollback();
throw;
}
}
}
}
/// <summary>
/// 执行一条计算查询结果语句，返回查询结果（object）。
/// </summary>
/// <param name="SQLString">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public static object GetSingle(string SQLString, params SQLiteParameter[] cmdParms)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand())
{
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
object obj = cmd.ExecuteScalar();
cmd.Parameters.Clear();
if (Equals(obj, null) || Equals(obj, DBNull.Value))
{
return null;
}
else
{
return obj;
}
}
catch (SQLiteException e)
{
throw new Exception(e.Message);
}
}
}
}
/// <summary>
/// 执行查询语句，返回SQLiteDataReader
/// </summary>
/// <param name="strSQL">查询语句</param>
/// <returns>SQLiteDataReader</returns>
public static SQLiteDataReader ExecuteReader(string SQLString, params SQLiteParameter[] cmdParms)
{
SQLiteConnection connection = new SQLiteConnection(connectionString);
SQLiteCommand cmd = new SQLiteCommand();
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
SQLiteDataReader myReader = cmd.ExecuteReader();
cmd.Parameters.Clear();
return myReader;
}
catch (SQLiteException e)
{
throw new Exception(e.Message);
}
}
/// <summary>
/// 执行查询语句，返回DataSet
/// </summary>
/// <param name="SQLString">查询语句</param>
/// <returns>DataSet</returns>
public static DataSet Query(string SQLString, params SQLiteParameter[] cmdParms)
{
using (SQLiteConnection connection = new SQLiteConnection(connectionString))
{
SQLiteCommand cmd = new SQLiteCommand();
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
using (SQLiteDataAdapter da = new SQLiteDataAdapter(cmd))
{
DataSet ds = new DataSet();
try
{
da.Fill(ds, "ds");
cmd.Parameters.Clear();
}
catch (SQLiteException ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}
}
private static void PrepareCommand(SQLiteCommand cmd, SQLiteConnection conn, SQLiteTransaction trans, string cmdText, SQLiteParameter[] cmdParms)
{
if (conn.State != ConnectionState.Open)
conn.Open();
cmd.Connection = conn;
cmd.CommandText = cmdText;
if (trans != null)
cmd.Transaction = trans;
cmd.CommandType = CommandType.Text;//cmdType;
if (cmdParms != null)
{
foreach (SQLiteParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}
#endregion
}
}