var result = from p in dc.People
join d in dc.Departments
on p.fk_dep_id equals d.pk_dep_id
select p;
return result.ToList();
The linq query above will select all People, together with the full name of the department they are assigned to. This result contains the Department data in an object "Department", which I can see when debugging.
However, when adding this result to a gridview, the joined data triggers an error:
"A field or property with the name "Department.name" was not found on the selected data source.
I tried doing the following in the Gridview:
<asp:BoudField DataField="Department.Name" HeaderText="Department" SortExpression="Department.Name" />
Any ideas on how to display such a "joined" columns in a Gridview, by using linq2sql data?
The DataField should be a property name of the object in the data source. You can't use complex expressions like that. For this you need the TemplateField:
<asp:TemplateField>
<ItemTemplate>
<asp:Label runat="server"
Text="<%# (Eval("Department") as Department).Name %>" />
</ItemTemplate>
</asp:TemplateField>
Related
i would like to know if there is a query to select values from all of my xml data fields. There are around 1k rows which has xml data. All of them has almost the same data structure. With extract value i was able to extract one data field but at the point where more than one row is part of my subquery it breaks.
Here is an example xml data inside my db:
<EDLXML version="1.0.0" type="variable">
<properties id="template_variables">
<deliveredDuration>4444</deliveredDuration>
<deliveredNum>1</deliveredNum>
<comment/>
<projectname>cdfkusen</projectname>
<name>kral_schalke_trenink</name>
<order_id>372846</order_id>
<cutlistId>2763_ID</cutlistId>
<bcutlistId>51ddgf7a6-1268-1gdfged-95e6-5254000e8e1a</bcutlistId>
<num>1</num>
<duration>177760</duration>
<quotaRelevantDuration>0</quotaRelevantDuration>
<organisationUid>OrgName</organisationUid>
<organisationQuota>333221233</organisationQuota>
<organisationUsedQuota>123</organisationUsedQuota>
<organisationContingentIrrelevantQuotaUsed>54</organisationContingentIrrelevantQuotaUsed>
<userDbId>7xxxx84-eb9b-11fdsb-9ddd1-52cccccde1a</userDbId>
<userId>xxxx</userId>
<userRights>RH_DBC</userRights>
<firstName>DThom</firstName>
<lastName>Test</lastName>
<userMail>xxx#ccc.cz</userMail>
<language>English</language>
<orderTimestamp>1659448080</orderTimestamp>
<stitching>false</stitching>
<transcode>NO</transcode>
<destination>Standard</destination>
<collaboration>private</collaboration>
<premiumUser>false</premiumUser>
<priority>normal</priority>
<userMail2>xxx#ccc.cz</userMail2>
<cutlistItems>
<cutListId>125124_KFC</cutListId>
<cutListItemId cutlistItemDeliveryStatus="✔" cutlistItemDStatusMessage="delivered">112799</cutListItemId>
<bmarkerId>8f16ff80-1269-11ed-95e6-5254000e8e1a</bmarkerId>
<videoId>2912799</videoId>
<counter>1</counter>
<frameInSpecified>true</frameInSpecified>
<frameIn>15638</frameIn>
<frameOutSpecified>true</frameOutSpecified>
<frameOut>20082</frameOut>
<tcIn>00:10:25:13</tcIn>
<tcOut>00:13:23:07</tcOut>
<duration>177760</duration>
<BroadcastDate>2021-07-24</BroadcastDate>
<eventDate>2021-07-24</eventDate>
<resolutionFacet>HD</resolutionFacet>
<provider>DBC</provider>
<technicalrightholders>RH_DBC</technicalrightholders>
<rights>DBC</rights>
<materialType>DP</materialType>
<targetFilename>kral_schalke_trenink</targetFilename>
</cutlistItems>
</properties>
</EDLXML>
I got the right value from query if i do:
SELECT ExtractValue((SELECT job_xml from cutlist where job_xml is not null LIMIT 1), '//deliveredNum');
But when i change the limit amount i get back: Subquery return more than one row.
extractvalue expects two string arguments. When your subquery returns more than one row, you are not simply passing a string as the first argument (you are passing a set of results).
Instead of calling extractvalue once for your entire query, call it once for every row, like:
SELECT ExtractValue(job_xml, '//deliveredNum')
FROM cutlist
WHERE job_xml IS NOT NULL
I have a tablix that has one dataset, and I need to hide one row based on a value in another dataset.
Currently I have this expression under visibility:
=Iif(Fields!Data1.Value="0" or Fields!Data2.Value="1", TRUE, FALSE)
Both of these are in another dataset called vDataset3.
Use this code
=IIF(First(Fields!UserID.Value, "DataSet2") = 0 or
First(Fields!UserID.Value, "DataSet2") = 12, True, False)
In order to call a field in another dataset you need to write:
First(Fields!UserID.Value, "DataSet2")
The first means that you take the first row. you have to do that because a dataset is like an array you must declare the field you would like to get.
and the "DataSet2" is the name of the dataset
I need further assistance with extracting records from XML and loading it into a SQL Server table.
I have this as my #xml:
<admin submitter_id="login0" effective_date="mm/dd/yyyy">
<rec effected_id="login1" adjustment="100.00" type="foo">
<reason reason_id="1" />
<reason reason_id="2" />
</rec>
<rec effected_id="login2" adjustment="50.00" type="bar">
<reason reason_id="3" />
</rec>
</admin>
I need this from a result set:
login0, login1, mm/dd/yyyy, 100.00, foo, 1
login0, login1, mm/dd/yyyy, 100.00, foo, 2
login0, login2, mm/dd/yyyy, 50.00, bar, 3
Does that make sense? The adjustment to the reason_id is one to many. I have figured out how to extract all the values except for the second line. I can only obtain the first reason_id and then it proceeds to the next record. I think this can be beaten with a CROSS APPLY but I cannot get it to work. Please help!
oh, I may also have received bogus XML. So if that's wrong, please tell me!
How about something like
DECLARE #Xml XML
SELECT #Xml = '<admin submitter_id="login0" effective_date="mm/dd/yyyy">
<rec effected_id="login1" adjustment="100.00" type="foo">
<reason reason_id="1" />
<reason reason_id="2" />
</rec>
<rec effected_id="login2" adjustment="50.00" type="bar">
<reason reason_id="3" />
</rec>
</admin>'
SELECT #Xml,
A2.B.value('(../../#submitter_id)[1]','VARCHAR(50)'),
A2.B.value('(../#effected_id)[1]','VARCHAR(50)'),
A2.B.value('(../../#effective_date)[1]','VARCHAR(50)'),
A2.B.value('(../#adjustment)[1]','FLOAT'),
A2.B.value('(../#type)[1]','VARCHAR(50)'),
A2.B.value('(#reason_id)[1]','INT')
FROM #XML.nodes('//admin/rec/reason') A2(B)
SQL Fiddle DEMO
Try to use this T-SQL code snippet:
SELECT
Submitter = #xml.value('(/admin/#submitter_id)[1]', 'varchar(50)'),
EffectedID = Rec.value('(#effected_id)[1]', 'varchar(50)'),
DateStamp = #xml.value('(/admin/#effective_date)[1]', 'varchar(50)'),
TypeID = Rec.value('(#type)[1]', 'varchar(50)'),
ReasonID = Reason.value('(#reason_id)[1]', 'int')
FROM
#xml.nodes('/admin/rec') AS Tbl(Rec)
CROSS APPLY
Rec.nodes('reason') AS T2(Reason)
It gives me an output of:
You need to have two nested lists of nodes - the first one grabs all the <rec> nodes from inside <admin>, while the second one iterates over all the <reason> nodes inside each of the <rec> nodes. That way, you can reliably extract all information from those two nested levels of subnodes, no matter how many subnodes there are on each level.
I am doing mysql queries execution from mybatis3.
I am new to this.
What is the difference between collection and association mapping in mybatis 3?
Specific example below.
SELECT e.empid AS empid,e.empname AS empname,
e.empsalary AS empsalary,p.proname AS proname,p.proid AS proid
FROM projects p,employees e,projectassigns pa
WHERE pa.empid=e.empid AND pa.proid=p.proid;
I need all the details of employee and project.
I have given the result map as follows.
<resultMap id="resultProjects" type="com.pratap.model.ProjAssigns">
<association property="employee" javaType="com.pratap.model.Employee"
resultMap="resultEmployees" />
<association property="project" javaType="com.pratap.model.Project"
resultMap="resultProjects" />
</resultMap>
Can anybody explain the difference taking my example or your own example?
I am confused with this..
Thank you.
I am going to assume that you have a many to many relationship between Projects and Employees, which is why you created a Project Assignment table. This Project Assignment table / object may only have two fields/columns: a mapping of project id to employee id - a classic "bridge table" (aka "join" or "junction" table).
When you map this model to an object graph, you have three options:
A Project object can have a list of all employees assigned to it
An Employee object can have a list of projects s/he is assigned to
Create a Project Assignment object that has a mapping of each projects to its employee and each employee to his/her project.
In your example you chose the last option.
Association
An association is a single mapping for a "has-one" relationship.
Suppose an Employee can only be assigned to one Project at a time. Some models call this a "has-one" or "belongs to" relationship. If you want to make Employee your "primary" focus in the object graph, then you would map it with an association to his/her Project:
<resultMap id="employeeResultMap" type="Employee">
<constructor>
<idArg column="employee_id" javaType="_integer"/>
</constructor>
<result property="firstName" column="first_name"/>
<result property="lastName" column="last_name"/>
<!-- etc. for other simple properties of Employee -->
<!-- Project is a "complex property" of Employee, so we use an -->
<!-- association to grab all of the Projects properties also -->
<association property="assignedProject" resultMap="projectResultMap"/>
</resultMap>
In this case your objects would look like this:
public Employee {
int id;
String firstName;
String lastName
Project assignedProject;
}
public Project {
int id;
String name;
String abc;
}
Collection
An collection is a "list" or "set" of associations.
Now model the inverse - we make Project the primary focus. A Project has a "has-many" relationship with Employee, so it will have a list or collection of those, so we use a "collection" mapping:
<resultMap id="projectResultMap" type="Project">
<constructor>
<idArg column="project_id" javaType="_integer"/>
<arg column="name" javaType="String"/>
</constructor>
<result property="abc" column="abc"/>
<!-- This tells mybatis that there can be multiple Employees -->
<!-- to look up and get their properties -->
<collection property="employees" ofType="Employee">
<constructor>
<idArg column="employee_id" javaType="_integer"/>
</constructor>
<result property="firstName" column="first_name"/>
<result property="lastName" column="last_name"/>
</collection>
</resultMap>
Now your objects would look like this:
public Employee {
int id;
String firstName;
String lastName
}
public Project {
int id;
String name;
String abc;
List<Employee> employees;
}
Project Association
To have a Project Association object, you would either need:
A single Project Association object that maps all projects to employees and vice versa
One Project Association object per project, mapping a project to its employees
One Project Association object per employee, mapping an employee to his/her projects
The first option is rather complex and messy - you would be trying to do relational mapping with object graphs (hash tables most likely).
I would choose to make one of the entities (Project or Employee) the primary focus and then model it as I showed above. The one case I didn't cover is if Employee is your primary focus and an Employee can be on multiple projects, then make that a "has-many" relationship using a collection rather than the association I used above.
Final Note: if it would help to see examples of using a "has-one" association and a "has-many" collection, see the MyBatis Koans I created: https://github.com/midpeter444/mybatis-koans. Koans 10 and 11 demonstrate this.
I have a JSP MySQL query
<sql:query var="libraries" dataSource="jdbc/ArabiTagOnline"><br>
SELECT l.LibraryId, v1.LAvalue AS "dbESTid", v2.LAValue AS "LibName", v3.LAValue AS "Desc"
FROM ((Library l LEFT JOIN LibAttrValue v1 ON l.LibraryId = v1.LibraryId AND v1.AttributeId = 1)
LEFT JOIN LibAttrValue v2 ON l.LibraryId = v2.LibraryId AND (v2.AttributeId = 2 OR v2.AttributeId IS NULL))
LEFT JOIN LibAttrValue v3 ON l.LibraryId = v3.LibraryId AND (v3.AttributeId = 6 OR v3.AttributeId IS NULL)
<\sql:query
This returns four columns.
I tried to rename the columns in the results with AS but when iterating over the results
<c:forEach var="libraryResults" items="${libraries.rows}">
<tr>
<td>${libraryResults.Libraryid}</td>
<td>${libraryResults.dbESTid}</td>
<td>${libraryResults.LibName}</td>
<td>${libraryResults.Desc}</td>
</tr>
</c:forEach>
When loading the page, the columns dbESTid, LibName and Desc are blank.
I asked ${libraries.columnNames} and found out the AS statement in my query didn't rename the columns, they are all still LAValue. ${libraryResults.LAValue} only returns Desc. Any help on how I can populate this table?
You don't need double quotes around column aliases in your SQL - that may be confusing the jdbc driver. Also, why the break tag within the <sql-query>?
Column aliasing should work. However, if the problem persists one possible workaround is to iterate over columns within each row:
<c:forEach var="libraryResults" items="${libraries.rows}">
<tr>
<c:forEach var="column" items="${libraryResults}">
<td><c:out value="${column.value}"/></td>
</c:forEach>
</tr>
</c:forEach>
That said, the real solution is, of course, to use an MVC framework so you don't have to embed your queries in JSP.