SQLITE3清空表

Posted 2023-04-27

参考技术A delete from tableName; //清空数据

update sqlite_sequence SET seq=0 where name='tableName';//自增长ID为0

Unsafe query: 'Delete' statement without 'where' clears all data in the table

遇到有删除约束问题的解决办法

可以选择一个能囊括所有记录的WHERE条件即可，一般有id的就 where id>0

sqlite数据库使用具体案例

本文操作是测试数据库的其中一张表，其中包括清空sqlite数据库MyGroup表中的数据，清空sqlite数据库sqlite_sequence表中的自增变量，sqlite数据库MyGroup直接插入数据 40000000，sqlite数据库MyGroup 参数插入数据 80000000

using System;
using System.Data;
using System.Data.SQLite;
using System.IO;
using System.Net;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace SupremeConsole
{
    class Program
    {
       static void Main(string[] args)
        {
            #region 测试sqlite数据库
            //GetSqliteData();
            GetSqliteData2();
            Thread.Sleep(TimeSpan.FromSeconds(10));
            GetSqliteData3();
            Thread.Sleep(TimeSpan.FromSeconds(10));
            GetSqliteData4();
            Thread.Sleep(TimeSpan.FromSeconds(10));
            GetSqliteData5();
            #endregion
            Console.ReadLine();
        }
         /// <summary>
        /// 使用sqlite获取数据
        /// </summary>
        public static void GetSqliteData()
        {
            SQLiteConnection sqLiteConn = new SQLiteConnection("Data source=" + Path.Combine(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Data"), "mysqlite.db"));
            sqLiteConn.Open();
            SQLiteCommand sqLiteCmd = new SQLiteCommand
            {
                Connection = sqLiteConn,
                CommandType = CommandType.Text,
                //CommandText = "select * from mydb"//DELETE FROM MyGroup;UPDATE sqlite_sequence SET seq = 0 WHERE name = ‘MyGroup‘;
            };

            SQLiteDataAdapter sqLiteDataAdapter = new SQLiteDataAdapter
            {
                SelectCommand = sqLiteCmd
            };
            DataSet dataSet = new DataSet();
            sqLiteDataAdapter.Fill(dataSet);
            sqLiteConn.Close();
            foreach (DataRow item in dataSet.Tables[0].Rows)
            {
                Console.WriteLine($"db_name：{item.ItemArray[2].ToString()}，hash_value：{item.ItemArray[3].ToString()}");
            }
            //string ss =$"编号：{dataSet.Tables[0].Rows[0].ItemArray[2].ToString()}，姓名：{dataSet.Tables[0].Rows[0].ItemArray[3].ToString()}";            
            //return ss;
        }

        /// <summary>
        /// 清空sqlite数据库MyGroup表中的数据
        /// </summary>
        public static void GetSqliteData2()
        {
            using (SQLiteConnection sqLiteConn = new SQLiteConnection("Data source=" + Path.Combine(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Data"), "mysqlite.db")))
            {
                sqLiteConn.Open();
                SQLiteTransaction sqLiteTransaction = sqLiteConn.BeginTransaction();
                SQLiteCommand sqLiteCmd = new SQLiteCommand
                {
                    Connection = sqLiteConn,
                    CommandType = CommandType.Text,
                    Transaction = sqLiteTransaction,
                    CommandText = "DELETE FROM MyGroup"//DELETE FROM MyGroup;UPDATE sqlite_sequence SET seq = 0 WHERE name = ‘MyGroup‘;
                };
                try
                {
                    int s = sqLiteCmd.ExecuteNonQuery();
                    Console.WriteLine($"清空sqlite数据库MyGroup表中的数据 ok");
                    sqLiteTransaction.Commit();

                }
                catch (Exception)
                {
                    Console.WriteLine($"清空sqlite数据库MyGroup表中的数据 error");
                    sqLiteTransaction.Rollback();
                    //throw;
                }
                finally
                {
                    sqLiteConn.Close();
                }
            }
        }

        /// <summary>
        /// 清空sqlite数据库sqlite_sequence表中的自增变量
        /// </summary>
        public static void GetSqliteData3()
        {
            SQLiteConnection sqLiteConn = new SQLiteConnection("Data source=" + Path.Combine(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Data"), "mysqlite.db"));
            sqLiteConn.Open();
            SQLiteTransaction sqLiteTransaction = sqLiteConn.BeginTransaction();
            try
            {
                SQLiteCommand sqLiteCmd = new SQLiteCommand
                {
                    Connection = sqLiteConn,
                    CommandType = CommandType.Text,
                    //CommandText = "select * from mydb"
                    Transaction = sqLiteTransaction,
                    CommandText = "UPDATE sqlite_sequence SET seq = 0 WHERE name = ‘MyGroup‘"//DELETE FROM MyGroup;UPDATE sqlite_sequence SET seq = 0 WHERE name = ‘MyGroup‘;
                };
                sqLiteCmd.ExecuteNonQuery();
                sqLiteTransaction.Commit();
                Console.WriteLine($"清空sqlite数据库sqlite_sequence表中的自增变量 ok");
            }
            catch (Exception)
            {
                sqLiteTransaction.Rollback();
                Console.WriteLine($"清空sqlite数据库sqlite_sequence表中的自增变量 error");
            }
            finally
            {
                sqLiteConn.Close();
            }
        }

        /// <summary>
        /// sqlite数据库MyGroup直接插入数据 40000000
        /// </summary>
        public static void GetSqliteData4()
        {
            SQLiteConnection sqLiteConn = new SQLiteConnection("Data source=" + Path.Combine(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Data"), "mysqlite.db"));
            sqLiteConn.Open();
            SQLiteTransaction sqLiteTransaction = sqLiteConn.BeginTransaction();
            try
            {
                SQLiteCommand sqLiteCmd = new SQLiteCommand
                {
                    Connection = sqLiteConn,
                    CommandType = CommandType.Text,
                    //CommandText = "select * from mydb"
                    Transaction = sqLiteTransaction,
                    CommandText = "INSERT INTO MyGroup (group_name, start_id, end_id) VALUES (‘group01‘, 0, 40000000)"//DELETE FROM MyGroup;UPDATE sqlite_sequence SET seq = 0 WHERE name = ‘MyGroup‘;
                };
                sqLiteCmd.ExecuteNonQuery();
                sqLiteTransaction.Commit();
                Console.WriteLine($"sqlite数据库MyGroup插入数据 40000000 ok");
            }
            catch (Exception)
            {
                sqLiteTransaction.Rollback();
                Console.WriteLine($"sqlite数据库MyGroup插入数据 40000000 error");
            }
            finally
            {
                sqLiteConn.Close();
            }
        }

        /// <summary>
        /// sqlite数据库MyGroup参数插入数据 80000000
        /// </summary>
        public static void GetSqliteData5()
        {
            SQLiteConnection sqLiteConn = new SQLiteConnection("Data source=" + Path.Combine(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Data"), "mysqlite.db"));
            sqLiteConn.Open();
            SQLiteTransaction sqLiteTransaction = sqLiteConn.BeginTransaction();
            try
            {       //INSERT INTO MyGroup (group_name, start_id, end_id) VALUES    ("group02",    40000000,    80000000);
                SQLiteCommand sqLiteCmd = new SQLiteCommand
                {
                    Connection = sqLiteConn,
                    CommandType = CommandType.Text,
                    Transaction = sqLiteTransaction,
                    CommandText = "INSERT INTO MyGroup (group_name, start_id, end_id) VALUES (@group_name, @start_id, @end_id)"//DELETE FROM MyGroup;UPDATE sqlite_sequence SET seq = 0 WHERE name = ‘MyGroup‘;
                };
                SQLiteParameter sQLiteParameter = new SQLiteParameter("@group_name", DbType.String);
                sQLiteParameter.Value = "group02";
                sqLiteCmd.Parameters.Add(sQLiteParameter);
                SQLiteParameter sQLiteParameter1 = new SQLiteParameter("@start_id", DbType.Int32);
                sQLiteParameter1.Value = 40000000;
                sqLiteCmd.Parameters.Add(sQLiteParameter1);
                SQLiteParameter sQLiteParameter2 = new SQLiteParameter("@end_id", DbType.Int32);
                sQLiteParameter2.Value = 80000000;
                sqLiteCmd.Parameters.Add(sQLiteParameter2);
                sqLiteCmd.ExecuteNonQuery();
                sqLiteTransaction.Commit();
                Console.WriteLine($"sqlite数据库MyGroup插入数据 80000000 ok");
            }
            catch (Exception)
            {
                sqLiteTransaction.Rollback();
                Console.WriteLine($"sqlite数据库MyGroup插入数据 80000000 error");
            }
            finally
            {
                sqLiteConn.Close();
            }
        }
      }
}

 

以上仅仅是根据本作者的sqlite数据库来写的操作，具体情况需要具体修改。

附加数据库：mysqlite.db