SQLiteHelper class:
using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.OleDb;
using System.Data.SQLite;
using System.Windows.Forms;
namespace TestSQLite
{
public class SqliteHelper
{
//连接字符串
private static string str ="Data source="+ AppDomain.CurrentDomain.BaseDirectory + "\\DATA.db";
/// <summary>
/// 增删改
/// 20180723
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="param">sql参数</param>
/// <returns>受影响的行数</returns>
public static int ExecuteNonQuery(string sql, params SQLiteParameter[] param)
{
try
{
using (SQLiteConnection con = new SQLiteConnection(str))
{
using (SQLiteCommand cmd = new SQLiteCommand(sql, con))
{
con.Open();
if (param != null)
{
cmd.Parameters.AddRange(param);
}
string sql2 = cmd.CommandText;
//con.Close();
the cmd.ExecuteNonQuery return ();
}
}
}
the catch (SQLiteException SE)
{
return 0;
}
}
/// <Summary>
/// CRUD
/// 20,180,723
/// </ Summary>
/// <param name = "sql"> sql statement </ param>
/// <param name = "param"> SQL parameters </ param>
/// <Returns> number of rows affected </ returns>
public static int ExecuteNonQuery(string sql)
{
try
{
using (SQLiteConnection con = new SQLiteConnection(str))
{
using (SQLiteCommand cmd = new SQLiteCommand(sql, con))
{
con.Open();
string sql2 = cmd.CommandText;
con.Close();
return cmd.ExecuteNonQuery();
}
}
}
catch (SQLiteException se)
{
return 0;
}
}
/// <summary>
/// 查询
/// 20180723
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="param">sql参数</param>
/// <returns>The first line of the first column </ returns>
public static object ExecuteScalar(string sql)
{
try
{
using (SQLiteConnection con = new SQLiteConnection(str))
{
using (SQLiteCommand cmd = new SQLiteCommand(con))
{
con.Open();
cmd.CommandText = sql;
return cmd.ExecuteScalar();
}
}
}
catch(Exception ex){
MessageBox.Show(ex.Message );
return null;
}
}
/// <summary>
/// 查询
/// 20180723
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="param">sql参数</param>
/// <returns>首行首列</returns>
public static object ExecuteScalar(string sql, params SQLiteParameter[] param)
{
using (SQLiteConnection con = new SQLiteConnection(str))
{
using (SQLiteCommand cmd = new SQLiteCommand(sql,with))
con.Open ();
{
if (param != null)
{
cmd.Parameters.AddRange(param);
}
return cmd.ExecuteScalar();
}
}
}
/// <summary>
/// 多行查询
/// 20180723
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="param">sql参数</param>
/// <returns>SQLiteDateReader</returns>
public static SQLiteDataReader ExecuteReader(string sql, params SQLiteParameter[] param)
{
using (SQLiteConnection con = new SQLiteConnection(str))
{
using (SQLiteCommand cmd = new SQLiteCommand(sql,with))
{
if (param != null)
{
cmd.Parameters.AddRange(param);
}
try
{
con.Open();
return cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
}
catch (Exception ex)
{
con.Close();
con.Dispose();
throw ex;
}
}
}
}
/// <summary>
/// 查询多行数据
/// 20180723
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="param">sql参数</param>
/// <returns>一个表</returns>
public static DataTable ExecuteTable(string sql, params SQLiteParameter[] param)
{
DataTable dt = new DataTable();
using (SQLiteDataAdapter sda = new SQLiteDataAdapter(sql, str))
{
if (param != null)
{
sda.SelectCommand.Parameters.AddRange(param);
}
sda.Fill(dt);
}
return dt;
/// 20180725
/// data insertion
}
/// <summary>
/// </ Summary>
/// <param name = "tbName"> table </ param>
/// <param name = "The insertData"> data dictionary to be inserted </ param>
/ // <returns> number of rows affected </ Returns>
public static int executelnsert (String tbName, the Dictionary <String, String> The insertData)
{
String Point = ""; // delimiter (,)
String keyStr = ""; / / field name string concatenation
string valueStr = ""; // string concatenation values
List <SQLiteParameter> param = new new List <SQLiteParameter> ();
the foreach (string Key in insertData.Keys)
{
keyStr string.Format + = ( "{0} `{1}`", point, key);
+ = string.Format valueStr ( "@ {{0}}. 1", Point, Key);
/// <Returns> number of rows affected </returns> );
param.Add(new SQLiteParameter("@" + key, insertData[key]));
point = ",";
}
string sql = string.Format("INSERT INTO `{0}`({1}) VALUES({2})", tbName, keyStr, valueStr);
//return sql;
return ExecuteNonQuery(sql, param.ToArray());
}
/// <summary>
/// 执行Update语句
/// 20180725
/// </summary>
/// <param name="tbName">表名</param>
/// <param name="where">更新条件：id=1</param>
/// <param name="insertData">需要更新的数据</param>
public static int ExecuteUpdate(string tbName, string where, Dictionary<String, String>The insertData)
String Point = ""; // delimiter (,)
{
string kvStr = "";//键值对拼接字符串(Id=@Id)
List<SQLiteParameter> param = new List<SQLiteParameter>();
foreach (string key in insertData.Keys)
{
kvStr += string.Format("{0} {1}=@{2}", point, key, key);
param.Add(new SQLiteParameter("@" + key, insertData[key]));
point = ",";
}
string sql = string.Format("UPDATE `{0}` SET {1} WHERE {2}", tbName, kvStr, where);
return ExecuteNonQuery(sql, param.ToArray());
}
/// <summary>
/// 查询
/// 20180723
/// </summary>
/// <param name = "sql"> sql statement </ param>
/// <param name="param">sql参数</param>
/// <returns>首行首列</returns>
public static DataTable GetDataTable(string sql)
{
try
{
using (SQLiteConnection con = new SQLiteConnection(str))
{
using (SQLiteCommand cmd = new SQLiteCommand(sql , con))
{
con.Open();
SQLiteDataAdapter ad = new SQLiteDataAdapter(cmd);
DataTable tb = new DataTable();
ad.Fill(tb);
con.Close();
return tb;
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
return null;
}
}
}
}
Test:
//see one value where .........
MessageBox.Show("" + SqliteHelper.ExecuteScalar("select uid from members where uid<>''"));
//see sql create syntax
DataTable tb = SqliteHelper.GetDataTable("select * from sqlite_master where name = 'members'");
MessageBox.Show("" + tb.Rows[0]["sql"]);
//or:
//string syntax = "" + SqliteHelper.ExecuteScalar("select sql from sqlite_master where name = 'members'");
//MessageBox.Show(syntax);
//see if column exists in table 'members'
bool hasCol = int.Parse("" + SqliteHelper.ExecuteScalar("select count(name) from sqlite_master where name = 'members' and sql like '%sendAccount%'")) > 0;
if (!hasCol)
{
//add column: ALTER TABLE table-name ADD COLUMN column-name column-type
SqliteHelper.ExecuteScalar("alter table members add COLUMN sendAccount varchar(20)");
//alter table student drop column name // 该行在SQlite中不能用，SQlite不支持drop
//SqliteHelper.ExecuteScalar("alter table members drop sendAccount33");
}
//drop table if exists A
string s = "" + SqliteHelper.ExecuteScalar("drop table if exists members2");
MessageBox.Show(s);
Reference: https: //blog.csdn.net/wuyou1336/article/details/53770799