query nullable colunn will always get null
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hi, i got this table - Employees: Id | Name ------------------ 1 Avi 2 jack 3 NULL 4 NULL 5 betty when i query this sql - "select id, name from employees" i get back a data set with 5 results. the problem is that its seems like when the query executed , when the query bump into a null value in the Name column, from now on all the results will be null. it means that the dataset result will be - Id | Name ------------------ 1 Avi 2 jack 3 NULL 4 NULL 5 NULL // SUPPOSE TO BE WITH "betty" why is that? (i accord to the problem when i tried to do ds.tables[0].rows[1][4] and it returned dbnull)
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hi, i got this table - Employees: Id | Name ------------------ 1 Avi 2 jack 3 NULL 4 NULL 5 betty when i query this sql - "select id, name from employees" i get back a data set with 5 results. the problem is that its seems like when the query executed , when the query bump into a null value in the Name column, from now on all the results will be null. it means that the dataset result will be - Id | Name ------------------ 1 Avi 2 jack 3 NULL 4 NULL 5 NULL // SUPPOSE TO BE WITH "betty" why is that? (i accord to the problem when i tried to do ds.tables[0].rows[1][4] and it returned dbnull)
Avi Laviad wrote: (i accord to the problem when i tried to do ds.tables[0].rows[1][4] and it returned dbnull) Given the SQL you gave, then this should fail. What you are saying in this piece of code is that you want the value from table[0] (the first table returned), Rows[1] (the second row, which should contain 2, Jack) and then column[4] (the fifth column is way outside the range - You should get an IndexOutOfRange exception if you run it) Perhaps, for brevity, you cut too much out of the code and we cannot see the problem anymore.
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Avi Laviad wrote: (i accord to the problem when i tried to do ds.tables[0].rows[1][4] and it returned dbnull) Given the SQL you gave, then this should fail. What you are saying in this piece of code is that you want the value from table[0] (the first table returned), Rows[1] (the second row, which should contain 2, Jack) and then column[4] (the fifth column is way outside the range - You should get an IndexOutOfRange exception if you run it) Perhaps, for brevity, you cut too much out of the code and we cannot see the problem anymore.
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i ment ds.tables[0].rows[4][1] - thats return me dbnull. my code is -
DataSet ds = DBHelper.Retrieve("select TreeId, owner, Root, BranchTitle, BranchText, LeafText, ScreenShot, Leaf_ScreenShot from Trees"); ArrayList list = new ArrayList(); if (ds.Tables[0].Rows.Count > 0) { for (int i=0; i < ds.Tables[0].Rows.Count; i++) { Tree t = new Tree(); if (ds.Tables[0].Rows[i][1] == DBNull.Value) { t.Owner = 0; } else { t.Owner = (double)ds.Tables[0].Rows[i][1]; } list.Add(t); } } else { throw new Exception("No rows found"); } return list;and DBHelpr.Retrieve code ispublic static DataSet Retrieve(string Sql) { DBFactory db = DBFactory.Instance; // getting db factory object IDbConnection conn = db.connect(Constants.ConnStr); // connecting to db IDbDataAdapter adapter = db.getAdapter(Sql, conn); DataSet ds = new DataSet(); adapter.Fill(ds); // querying data and filling dataset db.disconnect(ref conn); // disconnecting from db return ds; }any hint?