三、基本使用
1. 判断数据文件是否存在
/// <summary>
/// 检查数据库是否存在不存在创建
/// </summary>
/// <returns></returns>
public static bool CheckDataBase()
{
try
{
//判断数据文件是否存在
bool dbExist = File.Exists("mesclient.sqlite");
if (!dbExist)
{
SQLiteConnection.CreateFile("mesclient.sqlite");
}
return true;
}
catch (Exception)
{
return false;
}
}
2. 判断表是否存在
/// <summary>
/// 检查数据表是否存在，不存在创建
/// </summary>
/// <returns></returns>
public static bool CheckDataTable(string connStr)
{
try
{
using (SQLiteConnection conn = new SQLiteConnection(connStr))
using (SQLiteCommand cmd = conn.CreateCommand())
{
conn.Open();
cmd.CommandText = "SELECT count(*) FROM sqlite_master WHERE type = 'table' AND name = 'serverinfo'";
object ob = cmd.ExecuteScalar();
long tableCount = Convert.ToInt64(ob);
if (tableCount == 0)
{
//创建表
cmd.CommandText = @"
BEGIN;
create table serverinfo
(Id INTEGER PRIMARY KEY AUTOINCREMENT,Name TEXT,
Url text,DelayTime integer,UsageCounter INTEGER,
Status integer,CreateTime DATETIME);
CREATE UNIQUE INDEX idx_serverInfo ON serverinfo (Name);
COMMIT;
";
//此语句返回结果为0
int rowCount = cmd.ExecuteNonQuery();
return true;
}
else if (tableCount > 1)
{
return false;
}
else
{
return true;
}
}
}
catch (Exception ex)
{
return false;
}
}
3. 查询
string sql = "SELECT * FROM serverinfo WHERE Name =@ServerName AND Url = @Url and date(CreateTime)=date(@Date);";
Dictionary<string, object> parameters = new Dictionary<string, object>();
parameters.Add("ServerName",endpointElement.Name);
parameters.Add("Url", endpointElement.Address);
parameters.Add("Date", DateTime.Now.ToString("yyyy-MM-dd"));
DataTable dt=SqliteHelper.ExecuteQuery(connStr, sql, parameters);
if (dt.Rows.Count>0)
{
UsageCounter = dt.Rows[0].Field<long>("UsageCounter");
GetTime = dt.Rows[0].Field<DateTime>("CreateTime");
}
4. 新增/修改
