网上有许多介绍关于SQLite数据库的，这里我就不多说了，这里主要介绍SQLite数据库在C#中的应用，它的应用主要依赖于System.Data.SQLite.dll文件，可以点击这里下载https://pan.baidu.com/s/1dYVM53qiZAFbQkW6Re69ag。下载完成后直接引用到自己的工程里即可。好了废话不多说，直接上代码。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data.SQLite;
using System.IO; namespace InspectionQueue.CommonHelper
{
public class SqliteHelper
{
private static SqliteHelper _instance; public static SqliteHelper GetInstance()
{
if(null == _instance)
{
_instance = new SqliteHelper();
} return _instance;
}
/// <summary>
/// 数据库连接定义
/// </summary>
private SQLiteConnection dbConnection; /// <summary>
/// SQL命令定义
/// </summary>
private SQLiteCommand dbCommand; /// <summary>
/// 数据读取定义
/// </summary>
private SQLiteDataReader dataReader; private SqliteHelper() { }
public bool CreateDb(string dbPath)
{
try
{
if(!File.Exists(dbPath))
{
//如果数据库文件不存在,则创建
SQLiteConnection.CreateFile(dbPath);
}
string conDbPath = "Data Source=" + dbPath;
dbConnection = new SQLiteConnection(conDbPath);
if(null == dbConnection)
{
return false;
}
dbConnection.Open();
}
catch(Exception e)
{
throw e;
}
return true;
} /// <summary>
/// 执行SQL命令
/// </summary>
/// <param name="queryString"></param>
/// <returns></returns>
public SQLiteDataReader ExecuteQuery(string queryString)
{
try
{
dbCommand = dbConnection.CreateCommand();
dbCommand.CommandText = queryString;
dataReader = dbCommand.ExecuteReader();
}
catch(Exception e)
{
throw e;
} return dataReader;
} /// <summary>
/// 关闭数据库连接
/// </summary>
public void CloseConncetion()
{
//销毁Command
if(dbCommand != null)
{
dbCommand.Cancel();
}
dbCommand = null; //销毁Reader
if(dataReader != null)
{
dataReader.Close();
}
dataReader = null; //销毁Connection
if(dbConnection != null)
{
dbConnection.Clone();
}
dbConnection = null;
} /// <summary>
/// 读取整张数据表
/// </summary>
/// <param name="tableName"></param>
/// <returns></returns>
private SQLiteDataReader ReadFullTable(string tableName)
{
string queryString = "SELECT * FROM" + " " + tableName; return ExecuteQuery(queryString);
} /// <summary>
/// 向指定数据表中插入数据
/// </summary>
/// <param name="tableName"></param>
/// <param name="valus"></param>
/// <returns></returns>
public SQLiteDataReader InsertValue(string tableName, string[] valus)
{
//获取数据表中字段数目
int fieldCount = ReadFullTable(tableName).FieldCount;
//当插入的数据长度不等于字段数据时引异常
if(valus.Length != fieldCount)
{
throw new SQLiteException("values.Length != fileCount");
}
string queryString = "INSERT INTO" + " " + tableName + " " + "VALUES(" + "'" + valus[] + "'";
for (int i = ; i < valus.Length; i++)
{
queryString += "," + "'" + valus[i] + "'";
}
queryString += ")"; return ExecuteQuery(queryString);
} /// <summary>
/// 更新指定数据表内的数据
/// </summary>
/// <param name="tableName">数据表名称</param>
/// <param name="colNames">字段名</param>
/// <param name="colValues">字段名对应的数据</param>
/// <param name="key">关键字</param>
/// <param name="value">关键字对应的值</param>
/// <param name="operation">运算符:=,<,></param>
/// <returns></returns>
public SQLiteDataReader UpdateValues(string tableName, string[] colNames, string[] colValues, string key, string value, string operation)
{
//operation="=";//默认
//当字段名称和字段数值不对应时引发异常
if(colNames.Length != colValues.Length)
{
throw new SQLiteException("colNames.Length != colValues.Length");
}
string queryString = "UPDATE" + " "+ tableName + " " + "SET" + " "+ colNames[] + "=" + "'" + colValues[] + "'";
for (int i = ; i < colValues.Length; i++)
{
queryString += "," + colNames[i] + "=" + "'" + colValues[i] + "'";
}
queryString += "WHERE" + " " + key + operation + "'" + value + "'"; return ExecuteQuery(queryString);
} /// <summary>
/// 更新指定数据表中的数据
/// </summary>
/// <param name="tableName"></param>
/// <param name="colNames"></param>
/// <param name="colValues"></param>
/// <param name="key1"></param>
/// <param name="value1"></param>
/// <param name="operation"></param>
/// <param name="key2"></param>
/// <param name="value2"></param>
/// <returns></returns>
public SQLiteDataReader UpdateValues(string tableName, string[] colNames, string[] colValues,string key1, string value1, string operation, string key2, string value2)
{
//operation="=";默认
//当字段名称和字段数值不对应时发生异常
if(colNames.Length != colValues.Length)
{
throw new SQLiteException("colNames.Length != colValues.Length");
}
string queryString = "UPDATE" + " " + tableName + " " + "SET" + colNames[] + "=" + "'" + colValues[] + "'";
for(int i = ; i < colValues.Length; i++)
{
queryString += "," + colNames[i] + "=" + "'" + colValues[i] + "'";
}
//表中已经设置成int类型的不需要再次添加单引号,而字符串类型的数据需要进行添加单引号
queryString += "WHERE" + key1 + operation + "'" + value1 + "'" + "OR" + key2 + operation + "'" + value2 + "'"; return ExecuteQuery(queryString);
} /// <summary>
/// 删除指定数据表内的数据
/// </summary>
/// <param name="tableName">数据表名称</param>
/// <param name="colNames">字段名</param>
/// <param name="colValues">字段名对应的数据</param>
/// <param name="operations"></param>
/// <returns></returns>
public SQLiteDataReader DeleteValues(string tableName, string[] colNames, string[] colValues, string[] operations)
{
//当字段名称和字段数值不对应时引发异常
if(colNames.Length != colValues.Length || operations.Length != colNames.Length || operations.Length != colValues.Length)
{
throw new SQLiteException("colNames.Length != colValues.Length || operations.Length != colNames.Length || operations.Length != colValues.Length");
}
string queryString = "DELETE FROM" + " " + tableName + " " + "WHERE" + " " + colNames[] + operations[] + "'" + colValues[] + "'";
for(int i = ; i < colValues.Length; i++)
{
queryString += "AND" + " " + colNames[i] + operations[i] + "'" + colValues[i] + "'";
} return ExecuteQuery(queryString);
} /// <summary>
/// 创建数据表
/// </summary>
/// <param name="tableName"></param>
/// <param name="colNames"></param>
/// <param name="colTypes"></param>
/// <returns></returns>
public SQLiteDataReader CreateTable(string tableName, string[] colNames, string[] colTypes)
{
string queryString = "CREATE TABLE IF NOT EXISTS" +" " + tableName + "(" + colNames[] + " " + colTypes[];
for(int i = ; i < colNames.Length; i++)
{
queryString += "," + colNames[i] + " " + colTypes[i];
}
queryString += ")"; return ExecuteQuery(queryString);
} /// <summary>
/// 根据查询条件查询
/// </summary>
/// <param name="tableName"></param>
/// <param name="items"></param>
/// <param name="colNames"></param>
/// <param name="operations"></param>
/// <param name="colValues"></param>
/// <returns></returns>
public List<string[]> QueryTable(string tableName, string[] items, string[] colNames, string[] operations, string[] colValues)
{
string queryString = "SELECT" + " " + items[] + " ";
for(int i = ; i < items.Length; i++)
{
queryString += "," + items[i];
}
queryString += "FROM" + " " + tableName + " " + "WHERE" + " " + colNames[] + operations[] + "'" + colValues[] + "'";
for(int i = ; i < colNames.Length; i++)
{
queryString += "AND" + colNames[i] + " " + operations[i] + " " + "'" + colValues[i] + "'" + " ";
} SQLiteDataReader dr = ExecuteQuery(queryString);
List<string[]> QueryResult = new List<string[]>();
if(dr.HasRows)
{
while(dr.Read())
{
string[] queryData = new string[dr.FieldCount];
for (int i = ; i < dr.FieldCount; i++)
{
queryData[i] = dr.GetString(i);
}
QueryResult.Add(queryData);
}
} return QueryResult;
} /// <summary>
/// 查询整张数据表
/// </summary>
/// <param name="tableName"></param>
/// <returns></returns>
public List<string[]> QueryTable(string tableName)
{
string queryString = "SELECT" + " "+ "*FROM" + " " + tableName;
List<string[]> QueryResult = new List<string[]>();
if (null == QueryResult)
{
return null;
}
SQLiteDataReader dr = ExecuteQuery(queryString);
if(dr.HasRows)
{
while(dr.Read())
{
string[] queryData = new string[dr.FieldCount];
for (int i = ; i < dr.FieldCount; i++)
{
queryData[i] = dr[i].ToString();
}
QueryResult.Add(queryData);
}
} return QueryResult;
}
}
}