SQL: Selecting From Multiple Tables In One Query Or A Query For Each Table?
Mar 6, 2011
A follow up question concerning the DAL layer part .. The first question about dealing with large objectsI have one table (PlacesTable) that is connected by like 6 other tables (1:Many and Many:Many relations)
In my DAL should I put a big query that join the 6 tables + the m:m reference tables (btw it produces multiple data that I don't need Please refer to my old question) and place all the data in it's specific object property or, should I use a single query for each table and create an object for each fetched table .. and finally send those to the UI ?If I wasn't clear enough please let me know what I further information do you need to know!
have a database and I've created a DBML Linq-to-SQL file to represent this database. I've created a new aspx page and dropped a linqdatasource and a formview control onto it. When I configure the linqdatasource it gives me the choice only to select * from one table...but I want to pull from multiple tables. e.g. I have tables like simple_person, simple_address, simple_phone, and I want to pull from all of them.
how can I display a linq query in a gridview that has data from multiple tables AND allow the user to edit some of the fields or delete the data from a single table?
I'd like to do this with either a linqdatasource or a linq query. I'm aware I can set the e.Result to the query on the selecting event. I've also been able to build a custom databound control for displaying the linq relations (parent.child).
However, I'm not sure how I can make this work with delete? I'm thinking I may need to handle the delete event with custom code.
I have a view that has to render information from 3-4 tables. I therefore chose to create a viewModel for this. I am using EF as DAL.The information to be displayed is SiteId, SiteName, SiteDetails from one table.Associated to Site, other table Event_type has information about Events in the system with fileds like EventId, EventName, Event ScopeId.EventScope is another table with ScopeID and ScopeDesc Also, there is Site_Event_Implemnetation table that stores all the events associated to a site. It has SiteId, EventId, EventUnitIdEventUnit is another table that stores all the unit types.Now my Details ViewModel has to display the info SiteName, SiteDetails. And associated to that a grid of events with info on EventName, Scope Desc, Unit Desc1. How do I formulate my query to retrieve this info in my repository layer using Linq to EF?
Is there a way to select data from multiple tables other than the UNION ALL statement. Addtionally I need to select data from a different database.
My current statement is as follows (there are alot more fields but I have shortened it ):
SELECT server.dbo.SRFILE.SR_GROUP, server.dbo.SRFILE.SROWNERSHIP, server.dbo.SRFILE.SRCONMAE, BSFLBWF_1.Incidentx, BSFLBWF_1.Severityx FROM server.dbo.SRFILE INNER JOIN BSFLBWF AS BSFLBWF_1 ON BSFLBWF_1.Incidentx = server.dbo.SRFILE.SRONUMBER WHERE (BSFLBWF_1.Closex IS NULL).........
One of my peer wrote a query based on multiple tables using joins. One of the table is in a different database The query was taking much time
1. Create an SP 2. Create a temp table and copy all records from the external db 3. Avoid using Left Join as much as possible and use Inner Join 4. Create and use indexes 5. Remove tables/columns that are not necessary
In this scenario, I would like to suggest to use Covering Index, but how can it be created for multiple tables and a temp table?
I am trying to create statitics for game downloads and am having dificulty with a sub part of my query. the goup by command is not having the disired result and i think i have been looking at it too long to see what i am doing wrong. [Code]....
At the moment it is producing each result in many rows when only 4 rows should appear. its the download column that is doing it. needs to be sub queried or something to display total in relation to month,gameid,userid.
I have ajax ReorderList in my wep page,and I get the data from SQL Server.I would like to add table cells dynamically according to number of records and show the result side by side until for example I have five data in a row and then move to the next row,
I am new to sql so please bear with me here.I have two tables, COURSES and RESPONSES which have a common field userID. I am making a grid view which displays each users available courseName from the COURSES table and dateTaken from the RESPONSE table. So I simply wrote the query as:
SELECT c.*, r.* FROM COURSES c, RESPONSE r WHERE c.userID = @userID1 and r.userID = @userID1 and r.userResponse = NULL
I basically have a series of tables from one database that have an identical structure thus making retrieval of all records fairly easy (I just use a UNION ALL statement). However I need a list of values from another table within a different database that contains information regarding the group of the data.
I so far have the following:
SELECT Table1.* FROM Table1 UNION ALL SELECT Table2.* FROM Table2 UNION ALL SELECT Table3.* FROM Table3 UNION SELECT Database.dbo.SRFILE.SR_GROUP FROM Database.dbo.SRFILE INNER JOIN Database.dbo.SRFILE.SRONUMBER = Table1.Incidentx
I keep receiving a unable to parse message however all I need to retreive is the SR_GROUP value but just don't know the correct syntax. Is it actually possible to do this as the structure of SRFILE is not the same as Table1/2/3.
I've got a gridview that will allow clients to edit options they've already entered on another page. The gridview has three radio buttons in it each with a value of 1,2,3. The option value in the dataset is 1,2 or 3 respectively. I would like to have the radiobutton with the corresponding value selected in the gridview so they can see what they previously chose and will then be able to edit, if they wish.
How can I insert value in two tables by single sql query because if I'm using two sql query it gives problem me on binding data and connection. Like I have 2 table table 1, table 2 ... In table I'm only save id and name and in other table I'm saving id, time1, time2
i am developing a web site in Asp.Net using Visual Studio 2008.i want to know that how can i search a keyword that will be entered by the user, i want the key word should be searched in complete database(all the tables)using a single query.I am using sql database. how can the keyword be searched using like parameter...
As the title sugests, I am missing a (basic?) concept as I teach myself asp.net, linq, and C#. It has been awhile since I've done anything object oriented, so I don't know how much that is impacting this gap in my understanding. Anyhow, here is what I am trying to do. I have three SQL Server tables: PERSON, POSITION, AREA. There is a 1 to many relationship between PERSON and POSITION, and a 1 to 1 relationship between POSITION and AREA. Given the following code I verify who the person is who has logged into the browser:
[Code]....
I want to be able to return all of the AREAs the person is able to access, based on the position they currently hold. I am able to easily do this in a SQL Server query, and I am sure I can do this with a SQL stored procedure once I pass the EMPLOYEE_ID to the procedure. However, I would rather do this in the page_load event, and load the returned results into gridview1 for the viewer. The issue I am running into is in building the LINQ query. When I try to build it, I can only get access to two of the three tables, depending on which table I select with db. Is it possible to access all three tables in the same query?
I am a little new to this concept so bear with me.1) I need to query atleast 35 tables using linq to sql(SQL server database) . I am not able to add all the database entities in Linq to sql classes?
2)(View Model issue) When I use List<Reportcollection> and also List<Receipt> to convert the result then its giving an error that "Cannot convert list<anonymous> to list<string>"
Here I'm using three tables given below. As u can see in the below three tables, 3 columns(P_Id,PdtName,PdtImgUrl) are same. Now can any body tell me how can I retreive values of 3 columns(P_Id,PdtName,PdtImgUrl) without repeatition.
i have a form view that takes fields from two tables 'Contract' and 'volunteers', however because i used a query builder,i have to input an insert statement. How do i create an insert statement for two tables in one query?
1. I have a GridView on my page and it uses sqldatasource with parameterized query. What I want to do is, on page load (where nothing has been selected so no parameter supplied), I want it to query everything (something like SELECT * FROM [this_table]) but since my SelectCommand is something like
SELECT * FROM [this_table] WHERE [this_column] = @someParameters AND [that_column] = @someParameters.
Can I play around with default value to achieve something like that but how ? Now, when the page loads, it doesn't show anything (No Gridview).
2. On my page, I made something like (username, gender, address, and more) and one single search button. That means, no single control enable auto postback. What I am trying to accomplish is building dynamic query
(if username specifed -> SELECT * FROM [this_table] WHERE [username] LIKE @username).
If both username and gender are specified (SELECT * FROM [this_table] WHERE [username] LIKE @username AND [gender] = @gender) and you know the rest. How can I do this using GridView and SqlDataSource ? To my knowledge, I can only specify one SELECT statement in a sqldatasource.
