I have more than 3 tables. But for simplicity, let take 3 Products, ProductBrands and ProductAttributes. Every poduct have zero or more brands and zero or more attributes. Now I have,
SELECT P.Name,P.ID, P.Desc FROM Products
But I want to select all product attributes and brands in the same SQL. I am thinking this,
SELECT P.Name,P.ID, P.Desc, GetProductAttributesInJSONOrXML(P.ID), GetProductBrandsInJSONOrXML(P.ID) FROM Products
How to create GetProductAttributesInJSONOrXML and GetProductBrandsInJSONOrXML funstions? So that in my app I can easily deserilize the xml or json. Please let me know if there is a better way.
You can select data in SQL Server as XML by use of the FOR XML clause. Such a query will give you back a single row with a single column containing the generated XML. Here's an example.
You could use something like this:
SELECT Product.Name, Product.ID, Product.Desc, Attribs.Attribute, Brands.Brand
FROM Products Product
LEFT JOIN ProductBrands Brands ON Product.ID = Brands.ProductID
LEFT JOIN ProductAttributes Attribs ON Product.ID = Attribs.ProductID
FOR XML AUTO, ELEMENTS
To get XML schema something like this, with one Product group for each row:
<Product>
<Name></Name>
<ID></ID>
<Desc></Desc>
<Attribs>
<Attribute></Attribute>
</Attribs>
<Brands>
<Brand></Brand>
</Brands>
</Product>
...
There are a lot of different options with the clause to get the schema formatted exactly the way you want, though it might take a bit of work for more complicated designs.
There's no way to generate JSON on SQL Server, short of using code to explicitly generate it with text functions. This would be complicated and probably not perform very well, since SQL Server is not optimized for text processing. Generating JSON is best done at the application level.
If you need to emit both JSON and XML, I suggest generating both at the application level. This allows needing only one SQL query to get your data, and keeping the data formatting code in a single place.
If you want to do it in SQL server, here are the options:
Generate JSON String in Queries
Store JSON string in a column as string for faster rendering
You can also do it in java by using the JSON libarary mentioned in previous answer.
Related
I am trying to create a select query in access with two tables I want to link/create a relationship.
Normally, if both tables contains same value you can just "drag" and create a link between those two columns.
In this case however, the second table have an " /CUSTOMER" added at the end in the fields.
Example;
Table1.OrderNumber contains order numbers which always contains 10 characters
Table2.Refference contains same order numbers, but will have a " /CUSTOMER" added to the end.
Can I link/create a relationship between these two in a Query? And how?
Thanks for the help!
Sebastian
Table1.OrderNumber contains order numbers which always contains 10 characters
If so, try this join:
ON Table1.OrderNumber = Left(Table2.Reference, 10)
For these nuanced joins you will have to use SQL and not design view with diagram. Consider the following steps in MS Access:
In Design view, create the join as if two customer fields match exactly. Then run the query which as you point out should return no results.
In SQL view, find the ON clause and adjust to replace that string. Specifically, change this clause
ON Table1.OrderNumber = Table2.Refference
To this clause:
ON Table1.OrderNumber = REPLACE(Table2.Refference, '/CUSTOMER', '')
Then run query to see results.
Do note: with this above change, you may get an Access warning when trying to open query in Design View since it may not be able to be visualized. Should you ignore the warning, above SQL change may be reverted. Therefore, make any changes to query only in SQL view.
Alternatively (arguably better solution), consider cleaning out that string using UPDATE query on the source table so the original join can work. Any change to avoid complexity is an ideal approach. Run below SQL query only one time:
UPDATE Table2
SET Refference = REPLACE(Refference, '/CUSTOMER', '')
I've got a bigquery import from a firestore database where I want to query on a particular field from a document. This was populated via the firestore-bigquery extension and the document data is stored as a JSON string.
I'm trying to use a WHERE clause in my query that uses one of the fields from the JSON data. However this doesn't seem to work.
My query is as follows:
SELECT json_extract(data,'$.title') as title,p
FROM `table`
left join unnest(json_extract_array(data, '$.tags')) as p
where json_extract(data,'$.title') = 'technology'
data is the JSON object and title is an attribute of all of the items. The above query will run but yield 'no results' (There are definitely results there for the title in question as they appear in the table preview).
I've tried using WHERE title = 'technology' as well but this returns an error that title is an unrecognized field (hence the json_extract).
From my research this should work as a standard SQL JSON query but doesn't seem to work on Bigquery. Does anyone know of a way around this?
All I can think of is if I put the results in another table, but I don't know if that's a workable solution as the data is updated via the extension on an update, so I would need to constantly refresh my second table as well.
Edit
I'm wondering if configuring a view would help with this? Though ultimately I would like to query this based on different parameters and the docs here https://cloud.google.com/bigquery/docs/views suggest you can't reference query parameters in a view
I've since managed to work this out, and will share the solution for anyone else with the same problem.
The solution was to use JSON_VALUE in the WHERE clause instead e.g:
where JSON_VALUE(data,'$.title') = 'technology';
I'm still not sure if this is the best way to do this in terms of performance and cost so I will wait to see if anyone else leaves a better answer.
I have some relational data in a SQL Server 2008 database split across 3 tables, which I would like to use to populate some classes that represent them.
The hierarchy is: Products -> Variants -> Options.
I have considered passing back 3 result sets and using LINQ to check if there are any related/child records in the related tables. I've also considered passing back a single de-normalised table containing all of the data from the three tables and reading through the rows, manually figuring out where a product/variant/option begins and ends. Having little to no prior experience with LINQ, I opted to go for the latter, which sort of worked but required many lines of code for something that I had hoped would be pretty straight forward.
Is there an easier way of accomplishing this?
The end goal is to serialize the resulting classes to JSON, for use in a Web Service Application.
I've searched and searched on Google for an answer, but I guess I'm not searching for the right keywords.
After a bit of playing around, I've figured out a way of accomplishing this...
Firstly, create a stored procedure in SQL Server that will return the data as XML. It's relatively easy to generate an XML document containing hierarchical data.
CREATE PROCEDURE usp_test
AS
BEGIN
SELECT
1 AS ProductID
, 'Test' AS ProductDesc
, (
SELECT 1 AS VariantID
'Test'AS VariantDesc
FOR XML PATH('ProductVariant'), ROOT('ProductVariants'), TYPE
)
FOR XML PATH('Product'), ROOT('ArrayOfProduct'), TYPE
END
This gives you an XML document with a parent-child relationship:
<ArrayOfProduct>
<Product>
<ProductID>1</ProductID>
<ProductDesc>Test</ProductDesc>
<ProductVariants>
<ProductVariant>
<VariantID>1</VariantID>
<VariantDesc>Test</VariantDesc>
</ProductVariant>
</ProductVariants>
</Product>
</ArrayOfProduct>
Next, read in the results into the VB.Net application using a SqlDataReader. Declare an empty object to hold the data and deserialize the XML into the object using an XmlSerializer.
At this point, the data that once was in SQL tables is now represented as classes in your VB.Net application.
From here, you can then serialize the object into JSON using JavaScriptSerializer.Serialize.
I am not sure this is a duplicated question or not (I don't think so) but its very interesting question for me:
In SQL we can create custom field and put it in the result:
SELECT *.p, totalOrder=(SELECT sum(price) from orders where id=p.id)
FROM products p;
so the result is a list of products with totalSales value.
What is best approach in NoSQL(MongoDB),
I am sure we should have two types of socuments(products and orders) so I know we don't have Join but the question is do we have custom field assignment in finding queries?
When you use aggregation, you have the $project operation which is exactly that. It is used to rename fields or derive field values through some simple operators. But as usual with MongoDB, you can not get any data from another collection.
When you need to do something which is too complex to express with aggregation, you can use MapReduce and build your output-documents with Javascript. But again, no breaking out of the collection.
I have an application which I will be accessing SQL server to return data which has been filtered by selections from the application as any common faceted search. I did see some out the box solutions, but these are expensive and I prefer building out something custom, but just don't know where to start.
The database structure is like this:
The data from the PRODUCT table would be searched by tags from the TAG table. Values which would be found in the TAG table would be something like this:
ID NAME
----------------------
1 Blue
2 Green
3 Small
4 Large
5 Red
They would be related to products through the ProductTag table.
I would need to return two groups of data from this setup:
The Products that are only related to the Tags selected, whether single or multiple
The Remaining tags that are also available to select for the products which have already been refined by single or multiple selected tags.
I would like this to be all with-in SQL server if possible, 2 seperate as stored procedures.
Most websites have this feature built into it these days, ie: http://www.gnc.com/family/index.jsp?categoryId=2108294&cp=3593186.3593187 (They've called it 'Narrow By')
I have been searching for a while how to do this, and I'm taking a wild guess that if a stored procedure has to be created in this nature, that there would need to be 1 param that accepts CSV values, like this:
[dbo].[GetFacetedProducts] #Tags_Selected = '1,3,5'
[dbo].[GetFacetedTags] #Tags_Selected = '1,3,5'
So with this architecture, does anyone know what types of queries need to be written for these stored procedures, or is the architecture flawed in any way? Has anyone created a faceted search before that was like this? If so, what types of queries would be needed to make something like this? I guess I'm just having trouble wrap my head around it, and there isn't much out there that shows someone how to make something like this.
A RDBMS for being used for faceted searching is the wrong tool for the job at hand. Faceted searching is a multidimensional search, which is difficult to express in the set-based SQL language. Using a data-cube or the like might give you some of the desired functionality, but would be quite a bit of work to build.
When we were faced with similar requirements we ultimately decided to utilize the Apache Solr search engine, which supports faceting as well as many other search-oriented functions and features.
It is possible to do faceted search in SQL Server. However don't try to use your live product data tables. Instead create a de-normalised "fact" table which holds every product (rows) and every tag (columns) so that the intersection is your product-tag values. You can re-populate this periodically from your main product table.
It is then straightforward and relatively efficient to get the facet counts for the matching records for each tag the user checks.
The approach I have described will be perfectly good for small cases, e.g. 1,000 product rows and 50-100 tags (attributes). Also there is an interesting opportunity with the forthcoming SQL Server 2014, which can place tables in memory - that should allow much larger fact tables.
I have also used Solr, and as STW points out this is the "correct" tool for facet searches. It is orders of magnitude faster than a SQL Server solution.
However there are some major disadvantages to using Solr. The main issue is that you have to setup not only another platform (Solr) but also all the paraphernalia that goes with it - Java and some kind of Java servlet (of which there are several). And whilst Solr runs on Windows quite nicely, you will still soon find yourself immersed in a world of command lines and editing of configuration files and environment variables that will remind you of all that was great about the 1980s ... or possibly not. And when that is all working you then need to export your product data to it, using various methods - there is a SQL Server connector which works fairly well but many prefer to post data to it as XML. And then you have to create a webservice-type process on your application to send it the user's query and parse the resulting list of matches and counts back into your application (again, XML is probably the best method).
So if your dataset is relatively small, I would stick with SQL Server. You can still get a sub-second response, and SQL 2014 will hopefully allow much bigger datasets. If your dataset is big then Solr will give remarkably fast results (it really is very fast) but be prepared to make a major investment in learning and supporting a whole new platform.
There's other places where you can get examples of turning a CSV parameter into a table variable. Assuming you have done that part your query boils down to the following:
GetFacetedProducts:
Find Product records where all tags passed in are assigned to each product.
If you wrote it by hand you could end up with:
SELECT P.*
FROM Product P
INNER JOIN ProductTag PT1 ON PT1.ProductID = P.ID AND PT1.TagID = 1
INNER JOIN ProductTag PT2 ON PT1.ProductID = P.ID AND PT1.TagID = 3
INNER JOIN ProductTag PT3 ON PT1.ProductID = P.ID AND PT1.TagID = 5
While this does select only the products that have those tags, it is not going to work with a dynamic list. In the past some people have built up the SQL and executed it dynamically, don't do that.
Instead, lets assume that the same tag can't be applied to a product twice, so we could change our question to:
Find me products where the number of tags matching (dynamic list) is equal to the number of tags in (dynamic list)
DECLARE #selectedTags TABLE (ID int)
DECLARE #tagCount int
INSERT INTO #selectedTags VALUES (1)
INSERT INTO #selectedTags VALUES (3)
INSERT INTO #selectedTags VALUES (5)
SELECT #tagCount = COUNT(*) FROM #selectedTags
SELECT
P.ID
FROM Product P
JOIN ProductTag PT
ON PT.ProductID = P.ID
JOIN #selectedTags T
ON T.ID = PT.TagID
GROUP BY
P.ID,
P.Name
HAVING COUNT(PT.TagID) = #tagCount
This returns just the ID of products that match all your tags, you could then join this back to the products table if you want more than just an ID, otherwise you're done.
As for your second query, once you have the product IDs that match, you want a list of all tags for those product IDs that aren't in your list:
SELECT DISTINCT
PT2.TagID
FROM aProductTag PT2
WHERE PT2.ProductID IN (
SELECT
P.ID
FROM aProduct P
JOIN aProductTag PT
ON PT.ProductID = P.ID
JOIN #selectedTags T
ON T.ID = PT.TagID
GROUP BY
P.ID,
P.Name
HAVING COUNT(PT.TagID) = #tagCount
)
AND PT2.TagID NOT IN (SELECT ID FROM #selectedTags)