I am having a problem with the Dynamic Linq Library. I get a the following error "ParserException was unhandled by user code ')" or ','". I have a Dicitionary and I want to create a query based on this dictionary. So I loop through my dictionary and append to a string builder "PersonId = (GUID FROM DICTIONARY). I think the problem is were I append to PersonId for some reason I can't seem to convert my string guid to a Guid so the dynamic library don't crash.
I have tried this to convert my string guid to a guid, but no luck.
query.Append("(PersonId = Guid(" + person.Key + ")");
query.Append("(PersonId = " + person.Key + ")");
I am using VS 2010 RTM and RIA Services as well as the Entity Framework 4.
//This is the loop I use
foreach (KeyValuePair<Guid, PersonDetails> person in personsDetails)
{
if ((person.Value as PersonDetails).IsExchangeChecked)
{
query.Append("(PersonId = Guid.Parse(" + person.Key + ")");
}
}
//Domain service call
var query = this.ObjectContext.Persons.Where(DynamicExpression.ParseLambda<Person, bool>(persons));
Please help, and if you know of a better way of doing this I am open to suggestions.
For GUID comparison with dynamic linq use query properties and the Equals() method like in the provided sample.
var items = new[]
{
new { Id = Guid.Empty },
new { Id = Guid.NewGuid() },
new { Id = Guid.NewGuid() },
new { Id = Guid.NewGuid() }
};
var result = items.AsQueryable()
.Where("Id.Equals(#0)", Guid.Empty)
.Any();
Use a parameterized query, e.g.:
var query = this.ObjectContext.Persons.Where(
"PersonId = #1", new [] { person.Key } );
Did you try(notice the extra ')' ).
query.Append("(PersonId = Guid(" + person.Key + "))");
Related
I have some word templates(maybe thousands). Each template has merge fields which will be filled from database. I don`t like writing separate code for every template and then build the application and deploy it whenever a template is changed or a field on the template is added!
Instead, I'm trying to define all merge fields in a separate xml file and for each field I want to write the "query" which will be called when needed. EX:
mergefield1 will call query "Case.Parties.FirstOrDefault.NameEn"
mergefield2 will call query "Case.CaseNumber"
mergefield3 will call query "Case.Documents.FirstOrDefault.DocumentContent.DocumentType"
Etc,
So, for a particular template I scan its merge fields, and for each merge field I take it`s "query definition" and make that request to database using EntityFramework and LINQ. Ex. it works for these queries: "TimeSlots.FirstOrDefault.StartDateTime" or
"Case.CaseNumber"
This will be an engine which will generate word documents and fill it with merge fields from xml. In addition, it will work for any new template or new merge field.
Now, I have worked a version using reflection.
public string GetColumnValueByObjectByName(Expression<Func<TEntity, bool>> filter = null, string objectName = "", string dllName = "", string objectID = "", string propertyName = "")
{
string objectDllName = objectName + ", " + dllName;
Type type = Type.GetType(objectDllName);
Guid oID = new Guid(objectID);
dynamic Entity = context.Set(type).Find(oID); // get Object by Type and ObjectID
string value = ""; //the value which will be filled with data from database
IEnumerable<string> linqMethods = typeof(System.Linq.Enumerable).GetMethods(BindingFlags.Static | BindingFlags.Public).Select(s => s.Name).ToList(); //get all linq methods and save them as list of strings
if (propertyName.Contains('.'))
{
string[] properies = propertyName.Split('.');
dynamic object1 = Entity;
IEnumerable<dynamic> Child = new List<dynamic>();
for (int i = 0; i < properies.Length; i++)
{
if (i < properies.Length - 1 && linqMethods.Contains(properies[i + 1]))
{
Child = type.GetProperty(properies[i]).GetValue(object1, null);
}
else if (linqMethods.Contains(properies[i]))
{
object1 = Child.Cast<object>().FirstOrDefault(); //for now works only with FirstOrDefault - Later it will be changed to work with ToList or other linq methods
type = object1.GetType();
}
else
{
if (linqMethods.Contains(properies[i]))
{
object1 = type.GetProperty(properies[i + 1]).GetValue(object1, null);
}
else
{
object1 = type.GetProperty(properies[i]).GetValue(object1, null);
}
type = object1.GetType();
}
}
value = object1.ToString(); //.StartDateTime.ToString();
}
return value;
}
I`m not sure if this is the best approach. Does anyone have a better suggestion, or maybe someone has already done something like this?
To shorten it: The idea is to make generic linq queries to database from a string like: "Case.Parties.FirstOrDefault.NameEn".
Your approach is very good. I have no doubt that it already works.
Another approach is using Expression Tree like #Egorikas have suggested.
Disclaimer: I'm the owner of the project Eval-Expression.NET
In short, this library allows you to evaluate almost any C# code at runtime (What you exactly want to do).
I would suggest you use my library instead. To keep the code:
More readable
Easier to support
Add some flexibility
Example
public string GetColumnValueByObjectByName(Expression<Func<TEntity, bool>> filter = null, string objectName = "", string dllName = "", string objectID = "", string propertyName = "")
{
string objectDllName = objectName + ", " + dllName;
Type type = Type.GetType(objectDllName);
Guid oID = new Guid(objectID);
object Entity = context.Set(type).Find(oID); // get Object by Type and ObjectID
var value = Eval.Execute("x." + propertyName, new { x = entity });
return value.ToString();
}
The library also allow you to use dynamic string with IQueryable
Wiki: LINQ-Dynamic
I am using table-valued functions with Entity Framework 5. I just received this error:
A parameter named 'EffectiveDate' already exists in the parameter collection. Parameter names must be unique in the parameter collection. Parameter name: parameter
It is being caused by me joining the calls to table-valued functions taking the same parameter.
Is this a bug/limitation with EF? Is there a workaround? Right now I am auto-generating the code (.edmx file).
It would be really nice if Microsoft would make parameter names unique, at least on a per-context basis.
I've created an issue for this here.
In the meantime, I was able to get this to work by tweaking a few functions in the .Context.tt file, so that it adds a GUID to each parameter name at runtime:
private void WriteFunctionImport(TypeMapper typeMapper, CodeStringGenerator codeStringGenerator, EdmFunction edmFunction, string modelNamespace, bool includeMergeOption) {
if (typeMapper.IsComposable(edmFunction))
{
#>
[EdmFunction("<#=edmFunction.NamespaceName#>", "<#=edmFunction.Name#>")]
<#=codeStringGenerator.ComposableFunctionMethod(edmFunction, modelNamespace)#>
{ var guid = Guid.NewGuid().ToString("N"); <#+
codeStringGenerator.WriteFunctionParameters(edmFunction, " + guid", WriteFunctionParameter);
#>
<#=codeStringGenerator.ComposableCreateQuery(edmFunction, modelNamespace)#>
} <#+
}
else
{
#>
<#=codeStringGenerator.FunctionMethod(edmFunction, modelNamespace, includeMergeOption)#>
{ <#+
codeStringGenerator.WriteFunctionParameters(edmFunction, "", WriteFunctionParameter);
#>
<#=codeStringGenerator.ExecuteFunction(edmFunction, modelNamespace, includeMergeOption)#>
} <#+
if (typeMapper.GenerateMergeOptionFunction(edmFunction, includeMergeOption))
{
WriteFunctionImport(typeMapper, codeStringGenerator, edmFunction, modelNamespace, includeMergeOption: true);
}
} }
...
public void WriteFunctionParameters(EdmFunction edmFunction, string nameSuffix, Action<string, string, string, string> writeParameter)
{
var parameters = FunctionImportParameter.Create(edmFunction.Parameters, _code, _ef);
foreach (var parameter in parameters.Where(p => p.NeedsLocalVariable))
{
var isNotNull = parameter.IsNullableOfT ? parameter.FunctionParameterName + ".HasValue" : parameter.FunctionParameterName + " != null";
var notNullInit = "new ObjectParameter(\"" + parameter.EsqlParameterName + "\"" + nameSuffix + ", " + parameter.FunctionParameterName + ")";
var nullInit = "new ObjectParameter(\"" + parameter.EsqlParameterName + "\"" + nameSuffix + ", typeof(" + parameter.RawClrTypeName + "))";
writeParameter(parameter.LocalVariableName, isNotNull, notNullInit, nullInit);
}
}
...
public string ComposableCreateQuery(EdmFunction edmFunction, string modelNamespace)
{
var parameters = _typeMapper.GetParameters(edmFunction);
return string.Format(
CultureInfo.InvariantCulture,
"return ((IObjectContextAdapter)this).ObjectContext.CreateQuery<{0}>(\"[{1}].[{2}]({3})\"{4});",
_typeMapper.GetTypeName(_typeMapper.GetReturnType(edmFunction), modelNamespace),
edmFunction.NamespaceName,
edmFunction.Name,
string.Join(", ", parameters.Select(p => "#" + p.EsqlParameterName + "\" + guid + \"").ToArray()),
_code.StringBefore(", ", string.Join(", ", parameters.Select(p => p.ExecuteParameterName).ToArray())));
}
Not a bug. Maybe a limitation or an omission. Apparently this use case has never been taken into account. EF could use auto-created parameter names, but, yeah, it just doesn't.
You'll have to resort to calling one of the functions with .AsEnumerable(). For some reason, this must be the first function in the join (as I have experienced). If you call the second function with .AsEnumerable() it is still translated to SQL and the name collision still occurs.
I've seen elsewhere how to set the UnitPrice on an Item, using the wiley and elusive Item1 field as Intuit.Ipp.Data.Qbd.Money. But how do I READ the unit price from the Item1 field? I can't cast it. The new operator doesn't work ("new ...Money(myItem.Item1)"). So how do I get the price?
I realize the DevKit will probably never be changed so this makes sense. But can we at least get some doc explaining all those strange "xxxItemxxx" fields?
ServiceContext context = new ServiceContext(oauthValidator, realmId, intuitServiceType);
DataServices commonService = new DataServices(context);
Intuit.Ipp.Data.Qbd.Item qbdItem = new Intuit.Ipp.Data.Qbd.Item();
Intuit.Ipp.Data.Qbd.Money unitPrice = new Intuit.Ipp.Data.Qbd.Money();
unitPrice.Amount = 22;
unitPrice.AmountSpecified = true;
qbdItem.Item1 = unitPrice;
IEnumerable<Intuit.Ipp.Data.Qbd.Item> qbdItemsResult = commonService.FindAll(qbdItem, 1, 10) as IEnumerable<Intuit.Ipp.Data.Qbd.Item>;
foreach (var itemResult in qbdItemsResult)
{
Intuit.Ipp.Data.Qbd.Money test1UnitPrice = itemResult.Item1 as Intuit.Ipp.Data.Qbd.Money;
}
You can use the above code for .Net.
Response XML of Item entity suggests that 'UntiPrice' is a top level tag.
I tried this usecase using java. PFB code.
QBItemService itemService = QBServiceFactory.getService(context,QBItemService.class);
items = itemService.findAll(context,1, 100);
for (QBItem item : items) {
System.out.println("Name - " + item.getName() + " UnitPrice - " + item.getUnitPrice().getAmount());
Can you please try the same in .Net and let me know if it works in the same way.
Intuit.Ipp.Data.Qbd.Money [ getAmount() ]
Thanks
I am attempting to use Newtonsoft.Json.Net35 Version 4.0.2.0 to deserialize an ADO.NET DataTable that contains null values. Serialization works fine:
[Test]
public void SerializeDataTableWithNull()
{
var table = new DataTable();
table.Columns.Add("item");
table.Columns.Add("price", typeof(double));
table.Rows.Add("shirt", 49.99);
table.Rows.Add("pants", 54.99);
table.Rows.Add("shoes"); // no price
var json = JsonConvert.SerializeObject(table);
Assert.AreEqual(#"["
+ #"{""item"":""shirt"",""price"":49.99},"
+ #"{""item"":""pants"",""price"":54.99},"
+ #"{""item"":""shoes"",""price"":null}]", json);
}
Deserialization works fine if values are missing:
[Test]
public void DerializeDataTableWithImplicitNull()
{
const string json = #"["
+ #"{""item"":""shirt"",""price"":49.99},"
+ #"{""item"":""pants"",""price"":54.99},"
+ #"{""item"":""shoes""}]";
var table = JsonConvert.DeserializeObject<DataTable>(json);
Assert.AreEqual("shirt", table.Rows[0]["item"]);
Assert.AreEqual("pants", table.Rows[1]["item"]);
Assert.AreEqual("shoes", table.Rows[2]["item"]);
Assert.AreEqual(49.99, (double)table.Rows[0]["price"], 0.01);
Assert.AreEqual(54.99, (double)table.Rows[1]["price"], 0.01);
Assert.IsInstanceOf(typeof(System.DBNull), table.Rows[2]["price"]);
}
If, however, values are explicitly null:
[Test]
public void DerializeDataTableWithExplicitNull()
{
const string json = #"["
+ #"{""item"":""shirt"",""price"":49.99},"
+ #"{""item"":""pants"",""price"":54.99},"
+ #"{""item"":""shoes"",""price"":null}]";
var table = JsonConvert.DeserializeObject<DataTable>(json);
Assert.AreEqual("shirt", table.Rows[0]["item"]);
Assert.AreEqual("pants", table.Rows[1]["item"]);
Assert.AreEqual("shoes", table.Rows[2]["item"]);
Assert.AreEqual(49.99, (double)table.Rows[0]["price"], 0.01);
Assert.AreEqual(54.99, (double)table.Rows[1]["price"], 0.01);
Assert.IsInstanceOf(typeof(System.DBNull), table.Rows[2]["price"]);
}
DeserializeObject throws "System.ArgumentException : Cannot set Column 'price' to be null. Please use DBNull instead." The following workaround works for my particular JSON:
var regex = new Regex(#",?""[_\w]+"":null");
var nullless = regex.Replace(json, string.Empty);
var table = JsonConvert.DeserializeObject<DataTable>(nullless);
but like all regular expression-based kludges this is clearly brittle.
Finally, the questions:
Is this a bug?
Json.NET has many events that can be hooked. Is there a way to get notified when a when a null value is encountered and explicitly set the value to System.DBNull?
Thanks in advance,
Frank
It looks like this is a bug which is easily fixed by replacing
dr[columnName] = reader.Value
with
dr[columnName] = reader.Value ?? System.DBNull.Value
in Newtonsoft.Json.Converters.DataTableConverter. I have entered an issue in the tracker.
I'm attempting to parse SQL using the TSql100Parser provided by microsoft. Right now I'm having a little trouble using it the way it seems to be intended to be used. Also, the lack of documentation doesn't help. (example: http://msdn.microsoft.com/en-us/library/microsoft.data.schema.scriptdom.sql.tsql100parser.aspx )
When I run a simple SELECT statement through the parser it returns a collection of TSqlStatements which contains a SELECT statement.
Trouble is, the TSqlSelect statement doesn't contain attributes such as a WHERE clause, even though the clause is implemented as a class. http://msdn.microsoft.com/en-us/library/microsoft.data.schema.scriptdom.sql.whereclause.aspx
The parser does recognise the WHERE clause as such, looking at the token stream.
So, my question is, am I using the parser correctly? Right now the token stream seems to be the most useful feature of the parser...
My Test project:
public static void Main(string[] args)
{
var parser = new TSql100Parser(false);
IList<ParseError> Errors;
IScriptFragment result = parser.Parse(
new StringReader("Select col from T1 where 1 = 1 group by 1;" +
"select col2 from T2;" +
"select col1 from tbl1 where id in (select id from tbl);"),
out Errors);
var Script = result as TSqlScript;
foreach (var ts in Script.Batches)
{
Console.WriteLine("new batch");
foreach (var st in ts.Statements)
{
IterateStatement(st);
}
}
}
static void IterateStatement(TSqlStatement statement)
{
Console.WriteLine("New Statement");
if (statement is SelectStatement)
{
PrintStatement(sstmnt);
}
}
Yes, you are using the parser correctly.
As Damien_The_Unbeliever points out, within the SelectStatement there is a QueryExpression property which will be a QuerySpecification object for your third select statement (with the WHERE clause).
This represents the 'real' SELECT bit of the query (whereas the outer SelectStatement object you are looking at has just got the 'WITH' clause (for CTEs), 'FOR' clause (for XML), 'ORDER BY' and other bits)
The QuerySpecification object is the object with the FromClauses, WhereClause, GroupByClause etc.
So you can get to your WHERE Clause by using:
((QuerySpecification)((SelectStatement)statement).QueryExpression).WhereClause
which has a SearchCondition property etc. etc.
Quick glance around would indicate that it contains a QueryExpression, which could be a QuerySpecification, which does have the Where clause attached to it.
if someone lands here and wants to know how to get the whole elements of a select statement the following code explain that:
QuerySpecification spec = (QuerySpecification)(((SelectStatement)st).QueryExpression);
StringBuilder sb = new StringBuilder();
sb.AppendLine("Select Elements");
foreach (var elm in spec.SelectElements)
sb.Append(((Identifier)((Column)((SelectColumn)elm).Expression).Identifiers[0]).Value);
sb.AppendLine();
sb.AppendLine("From Elements");
foreach (var elm in spec.FromClauses)
sb.Append(((SchemaObjectTableSource)elm).SchemaObject.BaseIdentifier.Value);
sb.AppendLine();
sb.AppendLine("Where Elements");
BinaryExpression binaryexp = (BinaryExpression)spec.WhereClause.SearchCondition;
sb.Append("operator is " + binaryexp.BinaryExpressionType);
if (binaryexp.FirstExpression is Column)
sb.Append(" First exp is " + ((Identifier)((Column)binaryexp.FirstExpression).Identifiers[0]).Value);
if (binaryexp.SecondExpression is Literal)
sb.Append(" Second exp is " + ((Literal)binaryexp.SecondExpression).Value);
I had to split a SELECT statement into pieces. My goal was to COUNT how many record a query will return. My first solution was to build a sub query such as
SELECT COUNT(*) FROM (select id, name from T where cat='A' order by id) as QUERY
The problem was that in this case the order clause raises the error "The ORDER BY clause is not valid in views, inline functions, derived tables, sub-queries, and common table expressions, unless TOP or FOR XML is also specified"
So I built a parser that split a SELECT statment into fragments using the TSql100Parser class.
using Microsoft.Data.Schema.ScriptDom.Sql;
using Microsoft.Data.Schema.ScriptDom;
using System.IO;
...
public class SelectParser
{
public string Parse(string sqlSelect, out string fields, out string from, out string groupby, out string where, out string having, out string orderby)
{
TSql100Parser parser = new TSql100Parser(false);
TextReader rd = new StringReader(sqlSelect);
IList<ParseError> errors;
var fragments = parser.Parse(rd, out errors);
fields = string.Empty;
from = string.Empty;
groupby = string.Empty;
where = string.Empty;
orderby = string.Empty;
having = string.Empty;
if (errors.Count > 0)
{
var retMessage = string.Empty;
foreach (var error in errors)
{
retMessage += error.Identifier + " - " + error.Message + " - position: " + error.Offset + "; ";
}
return retMessage;
}
try
{
// Extract the query assuming it is a SelectStatement
var query = ((fragments as TSqlScript).Batches[0].Statements[0] as SelectStatement).QueryExpression;
// Constructs the From clause with the optional joins
from = (query as QuerySpecification).FromClauses[0].GetString();
// Extract the where clause
where = (query as QuerySpecification).WhereClause.GetString();
// Get the field list
var fieldList = new List<string>();
foreach (var f in (query as QuerySpecification).SelectElements)
fieldList.Add((f as SelectColumn).GetString());
fields = string.Join(", ", fieldList.ToArray());
// Get The group by clause
groupby = (query as QuerySpecification).GroupByClause.GetString();
// Get the having clause of the query
having = (query as QuerySpecification).HavingClause.GetString();
// Get the order by clause
orderby = ((fragments as TSqlScript).Batches[0].Statements[0] as SelectStatement).OrderByClause.GetString();
}
catch (Exception ex)
{
return ex.ToString();
}
return string.Empty;
}
}
public static class Extension
{
/// <summary>
/// Get a string representing the SQL source fragment
/// </summary>
/// <param name="statement">The SQL Statement to get the string from, can be any derived class</param>
/// <returns>The SQL that represents the object</returns>
public static string GetString(this TSqlFragment statement)
{
string s = string.Empty;
if (statement == null) return string.Empty;
for (int i = statement.FirstTokenIndex; i <= statement.LastTokenIndex; i++)
{
s += statement.ScriptTokenStream[i].Text;
}
return s;
}
}
And to use this class simply:
string fields, from, groupby, where, having, orderby;
SelectParser selectParser = new SelectParser();
var retMessage = selectParser.Parse("SELECT * FROM T where cat='A' Order by Id desc",
out fields, out from, out groupby, out where, out having, out orderby);