背景
Noob here - 无论如何,我正在构建一个c#表单应用程序,用于解析文本文件中的数据。我已将纺织品数据存储在列表中。
问题:
我不知道如何用这些数据填充sqlite表。如何将列表数据传输到sqlite表中的列中?
SQlite代码: (以下摘自finisar)
private void button4_Click(object sender, EventArgs e)
{
// [snip] - As C# is purely object-oriented the following lines must be put into a class:
// We use these three SQLite objects:
SQLiteConnection sqlite_conn;
SQLiteCommand sqlite_cmd;
SQLiteDataReader sqlite_datareader;
// create a new database connection:
sqlite_conn = new SQLiteConnection("Data Source=database.db;Version=3;New=True;Compress=True;");
// open the connection:
sqlite_conn.Open();
// create a new SQL command:
sqlite_cmd = sqlite_conn.CreateCommand();
// Let the SQLiteCommand object know our SQL-Query:
sqlite_cmd.CommandText = "CREATE TABLE test (id integer primary key, text varchar(100));";
// Now lets execute the SQL ;D
sqlite_cmd.ExecuteNonQuery();
// Lets insert something into our new table:
sqlite_cmd.CommandText = "INSERT INTO test (id, text) VALUES (1, 'Test Text 1');";
// And execute this again ;D
sqlite_cmd.ExecuteNonQuery();
// ...and inserting another line:
sqlite_cmd.CommandText = "INSERT INTO test (id, text) VALUES (2, 'Test Text 2');";
// And execute this again ;D
sqlite_cmd.ExecuteNonQuery();
// But how do we read something out of our table ?
// First lets build a SQL-Query again:
sqlite_cmd.CommandText = "SELECT * FROM test";
// Now the SQLiteCommand object can give us a DataReader-Object:
sqlite_datareader = sqlite_cmd.ExecuteReader();
// The SQLiteDataReader allows us to run through the result lines:
while (sqlite_datareader.Read()) // Read() returns true if there is still a result line to read
{
// Print out the content of the text field:
string data = sqlite_datareader.GetString(1);
MessageBox.Show(data);
}
// We are ready, now lets cleanup and close our connection:
sqlite_conn.Close();
}
所以这就是我要将列表数据传输到我的sqlite表的地方: sqlite_cmd.CommandText =“INSERT INTO test(id,text)VALUES(1,'Test Text 1');”;
我不知道究竟在哪里,或者如何在这里实现foreach循环语法。
由于
答案 0 :(得分:1)
从上面的代码中,您可能会注意到以下部分重复:
sqlite_cmd.CommandText = "INSERT INTO test (id, text) VALUES (..., ...);";
sqlite_cmd.ExecuteNonQuery();
所以,在这里你必须使用一个循环。
根据您阅读文本的方式,您必须使用适当的周期。
这是使用TextReader
:
using (StreamReader reader = File.OpenText("somefile.txt")) {
//Use a transaction: you should do bulk inserts inside transactions
DbTransaction tr = sqlite_conn.BeginTransaction();
//Create a command once.
DbCommand cmd = sqlite_conn.CreateCommand();
//Assign SQL with parameters (?)
cmd.CommandText = "INSERT INTO test (id, text) VALUES (?, ?);"
string line;
int line_num;
//Read all lines from file
for (line_num=0; (line = reader.ReadLine()) != null; ++line_num) {
//For each line, assign correct parameters
cmd.Parameters(0).Value=line_num;
cmd.Parameters(1).Value=line;
//Send command to database
cmd.ExecuteNonQuery();
}
//Commit - only at this point data is written to database
tr.Commit();
}