So method GetAllData is one of my universal methods for connecting to the database and here, since I have to add mupltiple records in once to the database I need to have one connetion with multiple commands to run. So my question is does this way of connection closes the database correctly, or if you have any improvments to my code please share with me.
var conn = new SqlConnection(ConnString);
conn.Open();
var data = new Dictionary<string, List<object>>();
foreach (var h in hours)
{
data += SqlUniversal.GetAllData(query,//idk how I will collect the data yet... i know += wouldnt work for dictionary
new[] {
//some parameters
},
conn);
}
//Here is the method, above is how I call it.
public static Dictionary<string, List<object>> GetAllData(string command, SqlParameter[] pars, SqlConnection conn)
{
if (conn == null)
{
conn = new SqlConnection(ConnString);
conn.Open();
}
var res = new Dictionary<string, List<object>>();
using (conn)
{
using (var cmd = new SqlCommand(command, conn))
{
cmd.Parameters.AddRange(pars);
using (var reader = cmd.ExecuteReader())
{
while (reader.Read())
for (var i = 0; i < reader.VisibleFieldCount; i++)
{
if (reader.GetValue(i) == DBNull.Value)
continue;
var name = reader.GetName(i);
if (res.ContainsKey(name))
res[name].Add(reader.GetValue(i));
else
res.Add(name, new List<object> {reader.GetValue(i)});
}
return res;
}
}
}
}
Probably the better way to do this is to let the overseeing method manage the connection:
public void SomeDataMethod()
{
using (var conn = new SqlConnection(ConnString))
{
conn.Open();
var data = new Dictionary<string, List<object>>();
foreach (var h in hours)
{
data += SqlUniversal.GetAllData(query,
new[] {
//some parameters
},
conn);
}
}
}
And remove the using (conn) from the GetData method:
public static Dictionary<string, List<object>> GetAllData(string command, SqlParameter[] pars, SqlConnection conn)
{
var res = new Dictionary<string, List<object>>();
using (var cmd = new SqlCommand(command, conn))
{
cmd.Parameters.AddRange(pars);
using (var reader = cmd.ExecuteReader())
{
//...
return res;
}
}
}
Now SomeDataMethod controls the connection lifetime and GetData doesn't worry about connection management.
Related
I am new to working in dot net. What I am trying to do is create a helper method which will fetch data from DB for any table. I have passed parameters dynamically it working fine. But when I try to read the data, I am finding it difficult to store the data in some collection. This I will be returning back to my calling point and bind it to a response type and return.
public static Dictionary<Dictionary<string, object>, object> GetData(SqlCommand cmd, string connectionString, List<SqlParameter> parameters)
{
try
{
SqlDataReader reader = null;
Dictionary<Dictionary<string,object>, object> returnObjects = new Dictionary<Dictionary<string, object>, object>();
Dictionary<string, object> returnObject = new Dictionary<string, object>();
using (SqlConnection sqlConnection = new SqlConnection(connectionString))
{
sqlConnection.Open();
cmd.Connection = sqlConnection;
cmd.CommandType = CommandType.StoredProcedure;
foreach (SqlParameter parameter in parameters)
{
cmd.Parameters.Add(parameter);
}
reader = cmd.ExecuteReader();
if (reader.HasRows)
{
while (reader.Read())
{
for (int i = 0; i < reader.FieldCount; i++)
{
returnObject.Add(reader.GetName(i), reader[i]);
}
returnObject.Clear();
returnObjects.Add(returnObject, reader);
}
}
}
return returnObjects;
}
catch (Exception ex)
{
throw;
}
}
In above code when i try to add in returnObjects dictionary it says key already added. Below is the code from where I am calling and patientResponse where I want to return.
Dictionary<Dictionary<string, object>, object> dct = new Dictionary<Dictionary<string, object>, object>();
dct = Helper.GetData(cmd, connectionString, parameters);
List<Patient_Response> pp = new List<Patient_Response>();
Patient_Response pr = new Patient_Response();
pr.Patient_Id = int.Parse(reader["ID"].ToString());
pr.FIRST_NAME = reader["FIRST_NAME"].ToString();
pr.LAST_NAME = reader["LAST_NAME"].ToString();
pr.phoneNumber = reader["TEL"].ToString();
pr.email = reader["EMAIL"].ToString();
pr.Address = reader["Address"].ToString();
pr.Gender = reader["Gender"].ToString();
pr.DOB = Convert.ToDateTime(reader["DOB"]).ToString("MM/dd/yyyy");
pp.Add(pr);
What i can use instead of dictionary so that i can get a collection returned.
What surely doesn't work in your code is that you add the same instance of returnObject for each row. You should put new Dictionary<string, object>() inside the while. Also, if your result set contains duplicate field names, you'll get an exception.
public static List<Dictionary<string, object>> GetData(SqlCommand cmd, string connectionString, List<SqlParameter> parameters)
{
try
{
SqlDataReader reader = null;
// changed this to be a list
List<Dictionary<string,object>> returnObjects = new List<Dictionary<string, object>>();
using (SqlConnection sqlConnection = new SqlConnection(connectionString))
{
sqlConnection.Open();
cmd.Connection = sqlConnection;
cmd.CommandType = CommandType.StoredProcedure;
foreach (SqlParameter parameter in parameters)
{
cmd.Parameters.Add(parameter);
}
reader = cmd.ExecuteReader();
if (reader.HasRows)
{
while (reader.Read())
{
// create a new returnObject for each row
Dictionary<string, object> returnObject = new Dictionary<string, object>();
for (int i = 0; i < reader.FieldCount; i++)
{
// following line throws an exception if there are multiple fields with the same name
returnObject.Add(reader.GetName(i), reader[i]);
}
returnObjects.Add(returnObject);
}
}
}
return returnObjects;
}
catch (Exception ex)
{
throw;
}
}
That said, there is not much benefit from first putting the content of reader into a list of dictionaries and then into a list of Patient_Response. You might as well directly fill a List<Patient_Response> from the reader (i.e. inside the while).
A generic way to do this might be (code is not verified to compile or run):
public static List<T> GetData<T>(
SqlCommand cmd,
string connectionString,
List<SqlParameter> parameters,
Func<IDataReader, T> readerToRow)
{
List<T> returnObjects = new List<T>();
using (SqlConnection sqlConnection = new SqlConnection(connectionString))
{
sqlConnection.Open();
cmd.Connection = sqlConnection;
cmd.CommandType = CommandType.StoredProcedure;
foreach (SqlParameter parameter in parameters)
{
cmd.Parameters.Add(parameter);
}
SqlDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
returnObjects.Add(readerToRow(reader));
}
}
return returnObjects;
}
// To call above function:
List<Patient_Response> pp = Helper.GetData(
cmd,
connectionString,
parameters,
reader =>
new Patient_Response
{
FIRST_NAME = reader["FIRST_NAME"].ToString(),
LAST_NAME = reader["LAST_NAME"].ToString(),
// more columns go here
}
);
I've got a problem with some queries from c# to SQL. I need to have a query executeReader and inside of it a if else that allow me to choose between two inserts queries. I'm calling a little external program(with the URL collected into the db) which allows me to choose between 1 and 2, if the 1 is chosen(pass) else(fail). I can't do that because the debug is giving me:
'A Command is yet associated with a DataReader opened, which needs to be closed.'
I don't know what to try anymore.
private void btnSTART_Click(object sender, RoutedEventArgs e)
{
sqliteCon.Open();
if (sqliteCon.State == System.Data.ConnectionState.Open)
{
string path = null;//estrazione1
SqlCommand cmd = new SqlCommand("select nomeI FROM tabL where selection=1", sqliteCon);
SqlDataReader nomeIRdr = null;//estrazione2
//qui
var scriptsToRun = new List<string>();
using (nomeIRdr = cmd.ExecuteReader())
{
while (nomeIRdr.Read())//estrazione4
{
path = nomeIRdr["nomeI"].ToString();//estrazione5
Process MyProc = Process.Start(path);//permette la run del path contenuto nel db
MyProc.WaitForExit();
var exitCode = MyProc.ExitCode;
if (exitCode == 1)
{
scriptsToRun.Add("insert into tabL resItem values 'PASS'");
}
else
{
scriptsToRun.Add("insert into tabL resItem values 'FAIL'");
}
sqliteCon.Close();
}
}
foreach (var script in scriptsToRun)
{
SqlCommand cmd1 = new SqlCommand(script, sqliteCon);
cmd1.ExecuteNonQuery();
}
}
}
Do not share single connection and cram everything into a single routine. Please, keep your code simple.
Create (and Dispose) Connection whenever you query RDBMS
Extract methods
Code:
Process execution and return execution results collection:
// Item1 - path
// Item2 - true in succeed
private List<Tuple<string, bool>> ExecuteResults() {
List<Tuple<string, bool>> result = new List<Tuple<string, bool>>();
using (var con = new SqlConnection(ConnectionStringHere)) {
con.Open();
string sql =
#"select nomeItem
from tabList
where selection = 1";
using (SqlCommand cmd = new SqlCommand(sql, con)) {
using (var reader = cmd.ExecuteReader()) {
while (reader.Read()) {
string path = Convert.ToString(reader[0]);
using (Process process = Process.Start(path)) {
process.WaitForExit();
result.Add(Tuple.Create(path, process.ExitCode == 1));
}
}
}
}
}
return result;
}
Saving results in RDBMS
private void ApplyExecuteResults(IEnumerable<Tuple<string, bool>> results) {
using (var con = new SqlConnection(ConnectionStringHere)) {
con.Open();
string sql =
#"update tabList
set resItem = #prm_resItem
where nomeItem = #prm_nomeItem";
using (SqlCommand cmd = new SqlCommand(sql, con)) {
cmd.Parameters.Add("#prm_nomeItem", SqlDbType.VarChar);
cmd.Parameters.Add("#prm_resItem", SqlDbType.VarChar);
foreach (var item in results) {
cmd.Parameters[0].Value = item.Item1;
cmd.Parameters[1].Value = item.Item2 ? "PASS" : "FAIL";
cmd.ExecuteNonQuery();
}
}
}
}
Finally, combine both routines:
private void btnSTART_Click(object sender, RoutedEventArgs e) {
ApplyExecuteResults(ExecuteResults());
}
I am trying to doing this:
Read a row from an SQLite db (in GetRuleByID() method)
Update the same row that I just read during (1) (See UpdateStatusForRuleID() method)
However my problem is that SQLite locks the database after the SELECT in GetRuleByID() so that update in UpdateStatusForRuleID() is only successful when called the first time.
I have tried enabling Write-Ahead-Logging in SQLite as well as PRAGMA read_uncommitted=1 in order to avoid SQLite locking the database for the SELECT, but this does not appear to work.
This should be simple but I have so far spent a complete night trying to solve this... Please help !
private static MicroRuleEngine.Rule GetRuleByID(int ruleID, SQLiteConnection connection, out Dictionary<string, string> dict)
{
dict = new Dictionary<string, string>();
string sql = String.Format("select * from rules WHERE ID = {0} ", ruleID.ToString());
SQLiteCommand command = new SQLiteCommand(sql, connection);
SQLiteDataReader reader = command.ExecuteReader();
if (reader.HasRows)
{
reader.Read();
// Convert row into a dictionary
for (int lp = 0; lp < reader.FieldCount; lp++)
{
dict.Add(reader.GetName(lp), reader.GetValue(lp) as string);
}
string json = dict["fulljson"];
MicroRuleEngine.Rule r = Newtonsoft.Json.JsonConvert.DeserializeObject<MicroRuleEngine.Rule>(json);
//command.Dispose();
return r;
}
}
internal static void UpdateStatusForRuleID(SQLConnectionManager DBMANAGER, int ruleID, bool status)
{
Dictionary<string, string> dict = null;
string dbVal = (status) ? "1" : "0";
MicroRuleEngine.Rule r = null;
string newJSON = null;
using (SQLiteConnection connection = DBMANAGER.CreateConnection())
{
r = GetRuleByID(ruleID, connection, out dict);
r.Active = (status);
newJSON = Newtonsoft.Json.JsonConvert.SerializeObject(r);
Thread.Sleep(1000);
string sql = "UPDATE rules SET active = #a, fulljson=#j WHERE ID = #i";
using (var command = new SQLiteCommand(sql, connection))
{
command.Parameters.Add(new SQLiteParameter("#a", dbVal));
command.Parameters.Add(new SQLiteParameter("#i", ruleID));
command.Parameters.Add(new SQLiteParameter("#j", newJSON));
command.ExecuteNonQuery(); // Database is locked here ???
}
connection.Close();
}
}
"Database is locked" means that some other connection (in the same or some other process) still has an active transaction.
You don't need multiple connections (unless you are using multiple threads); just use a single connection object for all database accesses.
Ensure that all command, reader, and transaction objects (and connections, if you decide to use temporary ones) are properly cleaned up, by using using:
using (var command = new SQLiteCommand(sql, connection))
using (var reader = command.ExecuteReader())
{
if (reader.HasRows)
...
}
Apparently, the code below works. I basically dropped the GetRuleByID() method (but then I had to re-write 4 other methods)
Thanks to all who provided input.
internal static void UpdateStatusForRuleID(SQLConnectionManager DBMANAGER, int ruleID, bool status)
{
string dbVal = (status) ? "1" : "0";
MicroRuleEngine.Rule r = null;
string newJSON = null;
using (SQLiteConnection conn = DBMANAGER.CreateConnection())
{
string sql = String.Format("select * from rules WHERE ID = {0} ", ruleID.ToString());
using (var command = new SQLiteCommand(sql, conn))
using (var reader = command.ExecuteReader())
{
if (reader.HasRows)
{
reader.Read();
string json = reader["fulljson"].ToString();
r = Newtonsoft.Json.JsonConvert.DeserializeObject<MicroRuleEngine.Rule>(json);
r.Active = (status);
newJSON = Newtonsoft.Json.JsonConvert.SerializeObject(r);
string sql2 = "UPDATE rules SET active = #a, fulljson=#j WHERE ID = #i";
using (var command2 = new SQLiteCommand(sql2, conn))
{
command2.Parameters.Add(new SQLiteParameter("#a", dbVal));
command2.Parameters.Add(new SQLiteParameter("#i", ruleID));
command2.Parameters.Add(new SQLiteParameter("#j", newJSON));
command2.ExecuteNonQuery();
}
}
}
}
}
I am trying to use SqlBulkCopy with ServiceStack Ormlite and have written the below extension method:
public static void BulkInsertSqlServer<T>(this IDbConnection dbConn, string targetTable, IEnumerable<T> data, params string[] columns)
{
Ensure.NotNull(dbConn);
Ensure.That(dbConn.State == ConnectionState.Open);
Ensure.NotNullOrEmptyOrWhiteSpace(targetTable);
Ensure.NotNull(data);
Ensure.NotNullOrEmpty(columns);
var sqlConnection = dbConn as SqlConnection;
using (var bcp = new SqlBulkCopy(sqlConnection))
using (var reader = ObjectReader.Create(data, columns))
{
bcp.BatchSize = data.Count();
bcp.DestinationTableName = targetTable;
bcp.WriteToServer(reader);
}
}
Which I am using by:
_connFactory = new OrmLiteConnectionFactory(connStr, SqlServerOrmLiteDialectProvider.Instance);
using (var db = _connFactory.Open())
using (var tran = db.BeginTransaction())
{
db.BulkInsertSqlServer("User", users, "Name", "Age");
var allRoles = new List<Role>();
foreach (var listOfRoles in users.Select(d => d.Roles))
{
allRoles.AddRange(listOfRoles);
}
db.BulkInsertSqlServer("Role", allRoles, "Name", "UserId", "IsAdmin");
tran.Commit();
}
However sqlConnection is always null, any ideas?
Because the connection is wrapped in a managed OrmLiteConnectionWrapper, you can get the SqlConnection with:
var adoNetConn = ((IHasDbConnection)dbConn).DbConnection;
var sqlConnection = adoNetConn as SqlConnection;
The list will grow and shrink depending on how many items I have in my database.
I need to populate a list not a listbox. I understand I will need to open a connection.
using (var conn = new SqlConnection(Properties.Settings.Default.DBConnectionString))
{
using (var cmd = conn.CreateCommand())
{
conn.Open();
List<string> TagList = new List<string>();
for (int i = 0; i < TagList.Count; i++)
TagList[i].Add("Data from database");
cmd.ExecuteNonQuery();
}
}
I'm really not sure how to do this and I'm sure my method up here looks very wrong so I really need help.
Could someone show me what I'm doing wrong?
public IEnumerable<string> GetTagList()
{
using (var connection = new SqlConnection(Properties.Settings.Default.DBConnectionString))
using (var cmd = connection.CreateCommand())
{
connection.Open();
cmd.CommandText = "select Tag from TagsTable"; // update select command accordingly
using (var reader = cmd.ExecuteReader())
{
while (reader.Read())
{
yield return reader.GetString(reader.GetOrdinal("Tag"));
}
}
}
}
then you can call it as below
List<string> tags = GetTagList().ToList();
I would like to share my solution, hope helps someone in the future:
public List<string> getFromDataBase()
{
List<string> result = new List<string>();
using(SqlConnection con = new SqlConnection("connectionString"))
{
con.Open();
DataTable tap = new DataTable();
new SqlDataAdapter(query, con).Fill(tap);
result = tap.Rows.OfType<DataRow>().Select(dr => dr.Field<string>("columnName")).ToList();
}
return result;
}
This would do as it is (if I didn't do any typos...)
private void LoadList()
{
List<string> tagsList = new List<string>();
using (IDbConnection connection = new SqlConnection(Properties.Settings.Default.DBConnectionString))
{
connection.Open();
using (IDbCommand command = connection.CreateCommand())
{
command.CommandText = "SELECT TAGCOLUMN FROM TAGSTABLE";
using (IDataReader reader = command.ExecuteReader())
{
while (reader.Read())
{
if (!reader.IsDBNull(0))
tagsList.Add(reader.GetString(0));
}
reader.Close();
}
}
connection.Close();
}
}
EDIT:
Of course you have to change the select statement to the correct one from your database.
I just used a pseudo one to show you what to put there.