How to properly get the Data Type of MS Access table
Below is my code:
var con = $"Provider=Microsoft.Jet.OLEDB.4.0;" +
$"Data Source={database};" +
"Persist Security Info=True;";
using (OleDbConnection myConnection = new OleDbConnection())
{
myConnection.ConnectionString = con;
myConnection.Open();
DataTable dt = myConnection.GetSchema("Tables");
var l = myConnection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new object[] { null, null, null, "TABLE" });
var isTableExist = false;
foreach (DataRow item in l.Rows)
{
var tbleName = item[2].ToString();
if (tbleName == tableName)
{
isTableExist = true;
break;
}
}
if (isTableExist)
{
string sql = string.Format($"SELECT * FROM {tableName}");
using (OleDbCommand cmd = new OleDbCommand(sql, myConnection))
{
using (OleDbDataReader reader = cmd.ExecuteReader())
{
if (reader != null)
{
for (int i = 0; i < reader.FieldCount; i++)
{
Console.WriteLine(reader.GetName(i));
Console.WriteLine(reader.GetDataTypeName(i));
}
}
}
}
}
}
Here is the structure of the mdb file im reading
And this is what i'm receiving
id
DBTYPE_I4
main_id
DBTYPE_I4
Document_ID
DBTYPE_WVARCHAR
End_page
DBTYPE_WVARCHAR
No_pages
DBTYPE_I4
Why does the AutoNumber datatype show the same as the number data type?
What i'm doing here is merging tables. And i want to skip the insert statement for those data type AutoNumber but i can't make it work because the result is the same with number. Thank you
Related
I am using oledb to read excel file and then i am trying to apply some conditions and then save in db, but i just want to read excel row one by one using loop.
var cmd = conn.CreateCommand();
cmd.CommandText = "select * from [الحيازات$]";// want to get this rows using loop so
//that only specific row is selected perform opertion blow then i will save in db,but
//its selecting all rows now
using (var rdr = cmd.ExecuteReader())
{
//LINQ query - when executed will create anonymous objects for each row
var query = (from DbDataRecord row in rdr
select row)
.Select(x =>
{
//dynamic item = new ExpandoObject();
Dictionary<string, string> item = new Dictionary<string, string>();
for (int i = 0; i < x.FieldCount; i++)
{
//code
}
});
}
Please check this
private void ReadExcel()
{
try
{
string connectionString = #"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + filePath + #";Extended Properties=""Excel 12.0;HDR=YES;IMEX=1;""";
using (OleDbConnection connection = new OleDbConnection())
{
connection.ConnectionString = connectionString;
using (OleDbCommand command = connection.CreateCommand())
{
command.CommandText = "SELECT * FROM [Sheet1$]";
connection.Open();
OleDbDataAdapter dataAdapter = new OleDbDataAdapter(command);
DataSet dataSet = new DataSet();
dataAdapter.Fill(dataSet);
if (dataSet != null && dataSet.Tables[0] != null)
{
foreach (DataRow row in dataSet.Tables[0].Rows)
{
string value = row["EmailColumnName"].ToString();
}
}
}
}
}
catch (Exception ex)
{
//Handle Exception
}
}
In my database table, I have a column name 'SectionDatatable' which are in XML datatype. In my C# code, after I have connection to database to my database and I make a query to get SectionDatatablewhich is XML format in my database, UserDefinedSectionData. I need to convert the 'SectionDatatable' in XML Datatype and convert it into DataSet, how can I do it. I have stuck for 1 day, the following is my code.
SqlConnectionStringBuilder csb = new SqlConnectionStringBuilder();
csb.DataSource = #"CPX-XSYPQKSA91D\SQLEXPRESS";
csb.InitialCatalog = "DNN_Database";
csb.IntegratedSecurity = true;
string connString = csb.ToString();
string queryString = "select * FROM UserDefinedSectionData WHERE SectionDataTabId = #tabId";
using (SqlConnection connection = new SqlConnection(connString))
using (SqlCommand command = connection.CreateCommand())
{
command.CommandText = queryString;
command.Parameters.Add(new SqlParameter("tabId", tabId));
connection.Open();
using (SqlDataReader reader = command.ExecuteReader())
{
while (reader.Read())
{
string sectionData= reader["SectionDatatable"].ToString();
int moduleId = Int32.Parse(reader["SectionDataModuleId"].ToString());
}
}
}
This is the simple example of converting XML string to DataSet. This sample also demonstrates processing all tables in DataSet.
You need to replace XML string in this sample with your XML output from database. You can change code as per you need to access data.
string RESULT_OF_SectionDatatable = "<note><to>Tove</to><from>Jani</from><heading>Reminder</heading><body>Don't forget me this weekend!</body></note>";
var xmlReader = XmlReader.Create(new StringReader(RESULT_OF_SectionDatatable));
DataSet ds = new DataSet();
ds.ReadXml(xmlReader);
foreach (DataTable table in ds.Tables)
{
Console.WriteLine(table);
Console.WriteLine();
foreach (var row in table.AsEnumerable())
{
for (int i = 0; i < table.Columns.Count; ++i)
{
Console.WriteLine(table.Columns[i].ColumnName +"\t" + row[i]);
}
Console.WriteLine();
}
}
I am having a hard time getting the codes that I need.
The code that I have created can get ALL the column names that I have listed regardless of having a value or not. What I only wanted to happen was to get the column names that has value(1).
I have this code:
internal static List<string> GetAllRoleTypeFromDatabase()
{
List<string> rolelist = new List<string>();
using (var con = new SQLiteConnection(sqliteConnectionMain.connectionString))
using (var cmd = new SQLiteCommand(con))
{
con.Open();
var _command = con.CreateCommand();
var queryq = string.Format("SELECT * FROM tblUserRoleAccess");
string commandText = queryq;
String sSQL;
sSQL = "SELECT * from tblUserRoleAccess";
cmd.CommandText = sSQL;
var dr = cmd.ExecuteReader();
for (var i = 1; i < dr.FieldCount; i++)
{
if (dr != null)
{
rolelist.Add(dr.GetName(i));
}
}
con.Close();
}
return rolelist;
}
Read a line in the reader (as i understand, there's only one row as a result).
For each column in the row check if its value is 1 (I used int, you should use the real type i.e. bool, string ...):
dr.Read();
for (var i = 1; i < dr.FieldCount; i++)
{
if (dr.GetFieldValue<int>(i) == 1)
{
rolelist.Add(dr.GetName(i));
}
}
I have a huge Excel file with around 50k rows. I am reading it using the following connection string
string.Format(#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties='Excel 12.0 Xml;HDR=No;IMEX=1'", MyFilePath);
In this huge Excel file, the rows are grouped in nesting pattern. Meaning, lets say first 500 rows are grouped under Group A there is a sub group in that group comprising of rows from 300-400 as Group B and then again from 350-400
in Group C. Now when I read the excel file in my program, I get all the rows, but I cannot distinguish between the row grouping I mentioned above. Is there any smart way to identify and group them accordingly?
Here's a sample of my code.
rivate List<List<string>> ReadSheetData(string _query, bool _HasHeaders = true)
{
string conn = "";
if (!_HasHeaders)
conn = string.Format(#"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={0};Extended Properties='Excel 12.0 Xml;HDR=No;IMEX=1'", MyFilePath);
else
conn = this.conn;
List<List<string>> ret = new List<List<string>>();
using (OleDbConnection connection = new OleDbConnection(conn))
{
connection.Open();
try
{
OleDbCommand command = new OleDbCommand(_query, connection);
using (OleDbDataReader dr = command.ExecuteReader())
{
DataTable tbl = dr.GetSchemaTable();
while (dr.Read())
{
List<string> rowVals = new List<string>();
ret.Add(rowVals);
for (int i = 0; i < dr.FieldCount; i++)
{
dynamic cell = dr[i];
string value = cell != null ? cell.ToString() : "";
rowVals.Add(value);
}
}
}
}
catch (Exception ex)
{ }
}
ret.RemoveAll(a => a.All(b => b == "") == true);
return ret;
}
I'm updating some old legacy code and I ran into a problem with the
SqlCommand.ExecuteReader() method. The problem is that it's not returning any
results. However, using SqlDataAdapter.Fill(), I get results back from the
database. What am I doing wrong? How can I get results back using the data
reader?
var connectionString = ConfigurationManager.ConnectionStrings["MyConnectionString"].ToString();
using (var sqlConnection = new SqlConnection(connectionString))
{
using (var sqlCommand = new SqlCommand())
{
sqlCommand.Connection = sqlConnection;
sqlCommand.CommandType = CommandType.Text;
sqlCommand.CommandText = "SELECT * FROM MyTable WHERE ID = 1";
sqlConnection.Open();
// This code works.
//var dataTable = new DataTable();
//using (var sqlDataAdapter = new SqlDataAdapter(sqlCommand))
//{
// sqlDataAdapter.Fill(dataTable);
//}
// This code is not working.
using (var sqlDataReader = sqlCommand.ExecuteReader())
{
while (sqlDataReader.Read())
{
// This fails because the data reader has no results.
var id = sqlDataReader.GetInt32(0);
}
}
}
}
Could it be that there is no Int32 in your results ?
var id = sqlDataReader.GetInt32(0); // <-- this might not be an Int32
Either try:
var id = sqlDataReader.GetValue(0);
Or cast to the correct type (BIGINT for example is Int64), not sure without seeing your data.
Try this..
var id = 0;
using (var sqlDataReader = sqlCommand.ExecuteReader())
{
while (sqlDataReader.Read())
{
id = sqlDataReader.GetInt32(sqlDataReader.GetOrdinal("ColName"));
}
}
I have moved the variable outside of the reader code or the variable will only be accessible inside that scope. I would avoid specifying the ordinal in the code, in case someone altered the columns in the DB.
Also, specify the columns in the SQL statement... SELECT ColName FROM ... and use params in the query
If you got to that line then it has results
Does not mean the value is not null
And you should not use a SELECT *
If may have a problem with an implicit cast
Try Int32
try
{
if(sqlDataReader.IsDBNull(0))
{
// deal with null
}
else
{
Int32 id = sqlDataReader.GetInt32(0);
}
}
catch (SQLexception Ex)
{
Debug.WriteLine(Ex.message);
}
var connectionString = ConfigurationManager.ConnectionStrings["MyConnectionString"].ToString();
using (var sqlConnection = new SqlConnection(connectionString))
{
sqlConnection.Open();
string sql = "SELECT * FROM MyTable WHERE ID = 1";
using (var sqlCommand = new SqlCommand(sql, sqlConnection))
{
using (var sqlDataReader = sqlCommand.ExecuteReader())
{
while (sqlDataReader.Read())
{
// This fails because the data reader has no results.
var id = sqlDataReader.GetInt32(0);
}
}
}
}