We have a storage table where we want to add a new integer column (It is in fact an enum of 3 values converted to int). We want a row to be required when:
It is an older row and the column does not exist
It is a new row and the column exists and does not match a particular value
When I just use a not equal operator on the column the old rows do not get returned. How can this be handled?
Update
Assuming a comparison always returns false for the non-existent column I tried somethinglike below (the value of the property will be always > 0 when it exists), which does not work either:
If the (Prop GreaterThanOrEqual -1) condition returns false I assume the value is null.
If not then, the actual comparison happens.
string propNullCondition = TableQuery.GenerateFilterConditionForInt(
"Prop",
QueryComparisons.GreaterThanOrEqual,
-1);
propNullCondition = $"{TableOperators.Not}({propNullCondition})";
string propNotEqualValueCondition = TableQuery.CombineFilters(
propNullCondition,
TableOperators.Or,
TableQuery.GenerateFilterConditionForInt(
"Prop",
QueryComparisons.NotEqual,
XXXX));
Note: The table rows written so far do not have "Prop" and only new rows will have this column. And expectation is the query should return all old rows and the new ones only when Prop != XXXX.
It seems that your code is correct, maybe there is a minor error there. You can follow my code below, which works fine as per my test:
Note: in the filter, the column name is case-sensitive.
CloudTableClient tableClient = storageAccount.CreateCloudTableClient();
CloudTable table = tableClient.GetTableReference("test1");
string propNullCondition = TableQuery.GenerateFilterConditionForInt(
"prop1", //note the column name shoud be case-sensitive here.
QueryComparisons.GreaterThanOrEqual,
-1);
propNullCondition = $"{TableOperators.Not}({propNullCondition})";
TableQuery<DynamicTableEntity> propNotEqualValueCondition = new TableQuery<DynamicTableEntity>()
.Where(
TableQuery.CombineFilters(
propNullCondition,
TableOperators.Or,
TableQuery.GenerateFilterConditionForInt(
"prop1",//note the column name shoud be case-sensitive here.
QueryComparisons.NotEqual,
2)));
var query = table.ExecuteQuery(propNotEqualValueCondition);
foreach (var q in query)
{
Console.WriteLine(q.PartitionKey);
}
The test result:
Here is my table in azure:
Related
Good Day,
I am querying my database using Linq and I have run into a problem, the query searched a column for a search phrase and based on if the column has the phrase, it then returns the results, The query is below,
Dim pdb = New ProductDataContext()
Dim query =
From a In pdb.tblUSSeries
Join b In pdb.tblSizes_ On a.Series Equals b.Series
Where
a.Series.ToString().Equals(searchString) Or
b.Description.Contains(searchString) Or Not b.Description.Contains(Nothing)
Order By b.Series, b.OrderCode Ascending
Select New CustomSearch With
{
.Series = a.Series,
.SeriesDescription= a.Description,
.Coolant = a.Coolant,
.Material = a.Material,
.Standard = a.Standard,
.Surface = a.Surface,
.Type = a.Type,
.PointAngle = a.PointAngle,
.DiaRange = a.DiaRange,
.Shank = b.Shank,
.Flutes = b.Flutes,
.EDPNum = b.EDPNum,
.SizesDescription = b.Description,
.OrderCode = b.OrderCode
}
Return query
I think the problem is that, in the table certain rows are NULL, so when it is checking the column for the phrase and it encounters a row that is null it, breaks and returns this error,
The cast to value type 'System.Int32' failed because the materialized value is null. Either the result type's generic parameter or the query must use a nullable type.
I have ran this query against another column that has all the rows populated with data and it returns the results ok.
So my question is how can I write it in VB to query the db with the supplied searchstring and return the results, when some of the rows in the columns have null values.
Any help would be great.
The exception occurs when you make the projection (i.e. select new CustomSearch)
And yes your trying to assign Null to some int property
(Not sure which one of your properties that is)
one of 2 choices :
1) Use nullalbe types for your properties (or just that one property).
2) project with an inline If ( ?? in C#) , I don't know VB so don't catch me on the syntax.
Taking Series just as an example i don't know if it's an int or if that's the problematic property
Select New CustomSearch With
{
.Series = If(a.Series Is Nothing,0, CInt(a.Series))
}
In C#
Select new CustomSearch
{
Series = a.Series ?? 0;
}
Using sql query on a DB and importing information into another DB. So, I want to change the value of a column if the date in Column B is less than a certain value.
e.g.- If Column B is less than 01/01/2015 then column A = 0, otherwise leave A alone.
I have tried a few variations my latest incarnation is which obviously doesn't work.
CASE
WHEN ColB <" + Constants.StartOfYear.ToString("yyyy-MM-dd") + #"
THEN ColA = 0
END
I use lots of other CASE statement and have already selected all my columns from the table
If I uderstand you right, all you want is update some values.
If it's your case, you can use UPDATE DML:
String sql =
#"update MyTable
set ColA = 0
where ColB < #prm_ColB"; // '#' - For MS SQL, ':' for Oracle etc.
then assign value to prm_ColB and execute it like that:
// Assuming that you're working with MS SQL
using (var con = new SqlConnection(YourConnectionString)) {
con.Connect();
using (var q = new SqlCommand(con)) {
q.CommandText = sql;
// Put actual parameter value here
q.Parameters.AddWithValue("#prm_ColB", new DateTime(DateTime.Now.Year, 1, 1));
q.ExecuteNonQuery();
}
}
give your RDBMS an actual DateTime value via binding variable (#prm_ColB) do not try converting the date into string for hardcoding.
I am trying to get data from SAP for analysis using RFC_READ_TABLE. It returns Fields correctly. However, when trying to get the rows it returns zero rows.
theFunc = functionCtrl.Add("RFC_READ_TABLE") '
Dim returnFunc As Boolean
Dim returnParam As Object
Dim retTab As Object
theFunc.exports("query_table") = "MSKA"
theFunc.exports("DELIMITER") = ";"
theFunc.exports("NO_DATA") = "TRUE"
theFunc.exports("ROWCOUNT") = "50"
returnFunc = theFunc.call
retTab = theFunc.tables("DATA")
msgbox retTab.rows.count ' >>>>>> returns 0
Last step returns zero as records count. The table contains data.When I search for table FIELDS , it returns the table fields correclty.
Is this related to security issues?
Regards,
Waleed
You're not getting any data returned because you're populating the NO_DATA parameter (which should be a single character anyway, not TRUE, for example). You're also not providing a WHERE clause (in the OPTIONS table parameter).
From the function module definition:
If you provide NO_DATA with a value of a single space (or omit it, as a single space is the default value) as well as a valid WHERE clause in OPTIONS, you should get data returned.
I am new to sharepoint, I have a custom field type derived from SpFieldChoice , my field allows users to select multiple values, I have a requirement of replacing some old custom columns with the new column and copy the data in old column to the new column. the old column also allows the users to select multiple values by ticking checkboxes, I have the following code to copy the data to new field.
foreach (SPListItem item in list.Items)
{
if (item[oldField.Title] == null)
{
item[newFld.Title] = string.Empty;
item.Update();
}
else
{
string[] itemvalues = item[oldField.Title].ToString().Split(new string[] {";#"}, StringSplitOptions.None);
StringBuilder multiLookupValues = new StringBuilder();
multiLookupValues.Append(";#");
for (int cnt = 0; cnt < (itemvalues.Length) / 2; cnt++)
{
multiLookupValues.Append (itemvalues[(cnt * 2) + 1].ToString() + ";#");
}
item[newFld.Title] = multiLookupValues.ToString();
item.SystemUpdate(false) ;
}
}
This code works fine until the length of resulting stringbuilder is less than 255 charachters , but when this length is greater then 255 I get the following Exception.
Invalid choice Value. A choice field contains invalid data.Please check the value and try again.
Is there any other way of copying data to SpFiledChoice, How can I resolve this problem? please help me.
Do the update multiple times so that the string doesn't exceed - i.e. value +=. However, if the problem is that the value can't be longer that 255, you have to consider how you are doing the choices. If it is exceeding the length and updating the value multiple times doesn't work (and a Site Column will have the same limitations), you can do the next best thing:
1) Create a new list that will hold the choices
2) Change the destination field to be a lookup
3) Update accordingly for each item (picking up the ID from the lookup field)
There's no limit to this.
David Sterling
david_sterling#sterling-consulting.com
www.sterling-consulting.com
I need to get maximum page order from database:
int maxOrder = GetSession.Query<Page>().Max(x => x.PageOrder);
The above works if there are rows in the database table, but when table is empty I'm getting:
Value cannot be null.
Parameter name: item
In the way you are doing it is normal to get an exception as the enumerable, that the GetSession.Query<Page>() returns, is empty (because the table is empty as you mentioned).
The exception that you should be getting is: Sequence contains no elements.
The exception you mention in your question is because the item variable (which is irrelevant with the NHiberanate query you list above) is null (line 54 assigns the item property to null).
A safer way to get the max from a property in a table would be the following:
var max = GetSession.CreateCriteria<Page>()
.SetProjection(Projections.Max("PageOrder"))
.UniqueResult();
or using QueryOver with NHibenrate 3.0:
var max = GetSession.QueryOver<Page>()
.Select(
Projections
.ProjectionList()
.Add(Projections.Max<Page>(x => x.PageOrder)))
.List<int>().First();
If the table is empty you will get max = 0
Session.Query<Page>().Max(x => (int?)x.PageOrder)
Note the cast (I'm assuming PageOrder is an int)
If you are having problems with the QueryOver example by tolism7 (InvalidCastException), here's how I got it working:
var max = session.QueryOver<Page>()
.Select(Projections.Max<Page>(x => x.PageOrder))
.SingleOrDefault<object>();
return max == null ? 0 : Convert.ToInt32(max);