Working on Azure Cognitive Search with backend as MS SQL table, have some scenarios where need help to define a query.
Sample table structure and data :
Scenarios 1 : Need to define a query which will return data based on category.
I have tied query using search.ismatch but its uses prefix search and matches other categories as well with similar kind of values i.e. "Embedded" and "Embedded Vision"
$filter=Region eq 'AA' and search.ismatch('Embedded*','Category')
https://{AZ_RESOURCE_NAME}.search.windows.net/indexes/{INDEX_NAME}/docs?api-version=2020-06-30-Preview&$count=true&$filter=Region eq 'AA' and search.ismatch('Embedded*','Category')
And it will response with below result, where it include "Embedded" and "Embedded Vision" both categories.
But my expectation is to fetch data only if it match "Embedded" category, as highlighted below
Scenario 2: For the above Scenario 1, Need little enhancement to find records with multiple category
For example if I pass multiple categories (i.e. "Embedded" , "Automation") need below highlighted output
you'll need to use a different analyzer which will break the tokens on every ';' just for the category field rather than 'whitespaces'.
You should first ensure your Category data is populated as a Collection(Edm.String) in the index. See Supported Data Types in the official documentation. Each of your semicolon-separated values should be separate values in the collection, in a property called Category (or similar).
You can then filter by string values in the collection. See rules for filtering string collections. Assuming that your index contains a string collection field called Category, you can filter by categories containing Embedded like this:
Category/any(c: c eq 'Embedded')
You can filter by multiple values like this:
Category/any(c: search.in(c, 'Embedded, Automation'))
Start with clean data in your index using proper types for the data you have. This allows you to implement proper facets and you can utilize the syntax made specifically for this. Trying to work around this with wildcards is a hack that should be avoided.
To solve above mention problem used a below SQL function which will convert category to a json string array supported by Collection(Edm.String) data type in Azure Search.
Sql Function
CREATE FUNCTION dbo.GetCategoryAsArray
(
#ID VARCHAR(20)
)
RETURNS NVARCHAR(MAX)
AS
BEGIN
DECLARE #result NVARCHAR(MAX) = ''
SET #result = REPLACE(
STUFF(
(SELECT
','''+ TRIM(Value) + ''''
FROM dbo.TABLEA p
CROSS APPLY STRING_SPLIT (Category, ';')
WHERE p.ID = #ID
FOR XML PATH('')
),1,1,''),'&','&')
RETURN '[' + #result + ']'
END
GO
View to use function and return desired data
CREATE View dbo.TABLEA_VIEW AS
select
id
,dbo. GetCategoryAsArray(id) as CategoryArr
,type
,region
,Category
from dbo.TABLEA
Defined a new Azure Search Index using above SQL View as data source and during Index column mapping defined CategoryArr column as Collection(Edm.String) data type
Query to use to achieve expected output from Azure Search
$filter=Region eq 'AA' and CategoryArr/any(c: search.in(c, 'Embedded, Automation'))
like the title mentions I want a Query that gets a random row of the existing database. After that I want to save the data which is in a specific column of that row in a variable for further purposes.
The query I have at the moment is as follows:
#Query("SELECT * FROM data_table ORDER BY RANDOM() LIMIT 1")
fun getRandomRow()
For now I am not sure if this query even works, but how would I go about writing my function to pass a specific column of that randomly selected row to a variable?
Ty for your advice, tips and/or solutions!
Your query is almost correct; however, you should specify a return type in the function signature. For example, if the records in the data_table table are mapped using a data class called DataEntry, then the query could read as shown below (note I've also added the suspend modifier so the query must be run using a coroutine):
#Query("SELECT * FROM data_table ORDER BY RANDOM() LIMIT 1")
suspend fun getRandomRow(): DataEntry?
If your application interacts with the database via a repository and view model (as described here: https://developer.android.com/topic/libraries/architecture/livedata) then the relevant methods would be along the lines of:
DataRepository
suspend fun findRandomEntry(): DataEntry? = dataEntryDao.getRandomRow()
DataViewModel
fun getRandomRecord() = viewModelScope.launch(Dispatchers.IO) {
val entry: DataEntry? = dataRepository.findRandomEntry()
entry?.let {
// You could assign a field of the DataEntry record to a variable here
// e.g. val name = entry.name
}
}
The above code uses the view model's coroutine scope to query the database via the repository and retrieve a random DataEntry record. Providing the returning DataEntry record is not null (i.e. your database contains data) then you could assign the fields of the DataEntry object to variables in the let block of the getRandomRecord() method.
As a final point, if it's only one field that you need, you could specify this in the database query. For example, imagine the DataEntry data class has a String field called name. You could retrieve this bit of information only and ignore the other fields by restructuring your query as follows:
#Query("SELECT name FROM data_table ORDER BY RANDOM() LIMIT 1")
suspend fun getRandomRow(): String?
If you go for the above option, remember to refactor your repository and view model to expect a String instead of a DataEntry object.
Ok
i have this class in my model :
i want to get the agencys value which is a many to many on this class and store them in a list or array . Agency which store agency_id with the id of my class on a seprate table.
Agency has it's own tabel as well
class GPSpecial(BaseModel):
hotel = models.ForeignKey('Hotel')
rooms = models.ManyToManyField('Room')
agencys = models.ManyToManyField('Agency')
You can make it a bit more compact by using the flat=True parameter:
agencys_spe = list(GPSpecial.objects.values_list('agencys', flat=True))
The list(..) part is not necessary: without it, you have a QuerySet that contains the ids, and the query is postponed. By using list(..) we force the data into a list (and the query is executed).
It is possible that multiple GPSpecial objects have a common Agency, in that case it will be repeated. We can use the .distinct() function to prevent that:
agencys_spe = list(GPSpecial.objects.values_list('agencys', flat=True).distinct())
If you are however interested in the Agency objects, for example of GPSpecials that satisfy a certain predicate, you better query the Agency objects directly, like for example:
agencies = Agency.objects.filter(gpspecial__is_active=True).distinct()
will produce all Agency objects for which a GPSpecial object exists where is_active is set to True.
I think i found the answer to my question:
agencys_sp = GPSpecial.objects.filter(agencys=32,is_active=True).values_list('agencys')
agencys_spe = [i[0] for i in agencys_sp]
I have a Insert object created as follows:
Insert insert = QueryBuilder.insertInto("demo", "users");
insert.value("name", name);
insert.value("sport", "test");
insert.value("years", 2);
insert.value("vegetarian", true);
Somewhere else in my code, I need to get the list of names and values associated with this INSERT object. When I debug the code I can see two "values" and "names" ArrayLists that contain the information I need, however they are private and I cannot access them.
While insert.getObject(0); gets the object from the values ArrayList, I can't map the value to a column name. Furthermore insert.getValues(ProtocolVersion.V4, CodecRegistry.DEFAULT_INSTANCE); seems to serialize the objects and put them into a ByteBuffer which is not desirable.
I recommend to use the PreparedStatement & BoundStatement instead of simple Insert. First, you can get better performance if you're inserting a lot of data. And second - you'll be able to get a list of variables defined in prepared statement, together with associated values
[UPDATE] Chosen approach is below, as a response to this question
Hi,
I' ve been looking around in this subject but I can't really find what I'm looking for...
With Code tables I mean: stuff like 'maritial status', gender, specific legal or social states... More specifically, these types have only set properties and the items are not about to change soon (but could). Properties being an Id, a name and a description.
I'm wondering how to handle these best in the following technologies:
in the database (multiple tables, one table with different code-keys...?)
creating the classes (probably something like inheriting ICode with ICode.Name and ICode.Description)
creating the view/presenter for this: there should be a screen containing all of them, so a list of the types (gender, maritial status ...), and then a list of values for that type with a name & description for each item in the value-list.
These are things that appear in every single project, so there must be some best practice on how to handle these...
For the record, I'm not really fond of using enums for these situations... Any arguments on using them here are welcome too.
[FOLLOW UP]
Ok, I've gotten a nice answer by CodeToGlory and Ahsteele. Let's refine this question.
Say we're not talking about gender or maritial status, wich values will definately not change, but about "stuff" that have a Name and a Description, but nothing more. For example: Social statuses, Legal statuses.
UI:
I want only one screen for this. Listbox with possibe NameAndDescription Types (I'll just call them that), listbox with possible values for the selected NameAndDescription Type, and then a Name and Description field for the selected NameAndDescription Type Item.
How could this be handled in View & Presenters? I find the difficulty here that the NameAndDescription Types would then need to be extracted from the Class Name?
DB:
What are pro/cons for multiple vs single lookup tables?
Using database driven code tables can very useful. You can do things like define the life of the data (using begin and end dates), add data to the table in real time so you don't have to deploy code, and you can allow users (with the right privileges of course) add data through admin screens.
I would recommend always using an autonumber primary key rather than the code or description. This allows for you to use multiple codes (of the same name but different descriptions) over different periods of time. Plus most DBAs (in my experience) rather use the autonumber over text based primary keys.
I would use a single table per coded list. You can put multiple codes all into one table that don't relate (using a matrix of sorts) but that gets messy and I have only found a couple situations where it was even useful.
Couple of things here:
Use Enumerations that are explicitly clear and will not change. For example, MaritalStatus, Gender etc.
Use lookup tables for items that are not fixed as above and may change, increase/decrease over time.
It is very typical to have lookup tables in the database. Define a key/value object in your business tier that can work with your view/presentation.
I have decided to go with this approach:
CodeKeyManager mgr = new CodeKeyManager();
CodeKey maritalStatuses = mgr.ReadByCodeName(Code.MaritalStatus);
Where:
CodeKeyManager can retrieve CodeKeys from DB (CodeKey=MaritalStatus)
Code is a class filled with constants, returning strings so Code.MaritalStatus = "maritalStatus". These constants map to to the CodeKey table > CodeKeyName
In the database, I have 2 tables:
CodeKey with Id, CodeKeyName
CodeValue with CodeKeyId, ValueName, ValueDescription
DB:
alt text http://lh3.ggpht.com/_cNmigBr3EkA/SeZnmHcgHZI/AAAAAAAAAFU/2OTzmtMNqFw/codetables_1.JPG
Class Code:
public class Code
{
public const string Gender = "gender";
public const string MaritalStatus = "maritalStatus";
}
Class CodeKey:
public class CodeKey
{
public Guid Id { get; set; }
public string CodeName { get; set; }
public IList<CodeValue> CodeValues { get; set; }
}
Class CodeValue:
public class CodeValue
{
public Guid Id { get; set; }
public CodeKey Code { get; set; }
public string Name { get; set; }
public string Description { get; set; }
}
I find by far the easiest and most efficent way:
All code-data can be displayed in a identical manner (in the same view/presenter)
I don't need to create tables and classes for every code table that's to come
But I can still get them out of the database easily and use them easily with the CodeKey constants...
NHibernate can handle this easily too
The only thing I'm still considering is throwing out the GUID Id's and using string (nchar) codes for usability in the business logic.
Thanks for the answers! If there are any remarks on this approach, please do!
I lean towards using a table representation for this type of data. Ultimately if you have a need to capture the data you'll have a need to store it. For reporting purposes it is better to have a place you can draw that data from via a key. For normalization purposes I find single purpose lookup tables to be easier than a multi-purpose lookup tables.
That said enumerations work pretty well for things that will not change like gender etc.
Why does everyone want to complicate code tables? Yes there are lots of them, but they are simple, so keep them that way. Just treat them like ever other object. Thy are part of the domain, so model them as part of the domain, nothing special. If you don't when they inevitibly need more attributes or functionality, you will have to undo all your code that currently uses it and rework it.
One table per of course (for referential integrity and so that they are available for reporting).
For the classes, again one per of course because if I write a method to recieve a "Gender" object, I don't want to be able to accidentally pass it a "MarritalStatus"! Let the compile help you weed out runtime error, that's why its there. Each class can simply inherit or contain a CodeTable class or whatever but that's simply an implementation helper.
For the UI, if it does in fact use the inherited CodeTable, I suppose you could use that to help you out and just maintain it in one UI.
As a rule, don't mess up the database model, don't mess up the business model, but it you wnt to screw around a bit in the UI model, that's not so bad.
I'd like to consider simplifying this approach even more. Instead of 3 tables defining codes (Code, CodeKey and CodeValue) how about just one table which contains both the code types and the code values? After all the code types are just another list of codes.
Perhaps a table definition like this:
CREATE TABLE [dbo].[Code](
[CodeType] [int] NOT NULL,
[Code] [int] NOT NULL,
[CodeDescription] [nvarchar](40) NOT NULL,
[CodeAbreviation] [nvarchar](10) NULL,
[DateEffective] [datetime] NULL,
[DateExpired] [datetime] NULL,
CONSTRAINT [PK_Code] PRIMARY KEY CLUSTERED
(
[CodeType] ASC,
[Code] ASC
)
GO
There could be a root record with CodeType=0, Code=0 which represents the type for CodeType. All of the CodeType records will have a CodeType=0 and a Code>=1. Here is some sample data that might help clarify things:
SELECT CodeType, Code, Description FROM Code
Results:
CodeType Code Description
-------- ---- -----------
0 0 Type
0 1 Gender
0 2 Hair Color
1 1 Male
1 2 Female
2 1 Blonde
2 2 Brunette
2 3 Redhead
A check constraint could be added to the Code table to ensure that a valid CodeType is entered into the table:
ALTER TABLE [dbo].[Code] WITH CHECK ADD CONSTRAINT [CK_Code_CodeType]
CHECK (([dbo].[IsValidCodeType]([CodeType])=(1)))
GO
The function IsValidCodeType could be defined like this:
CREATE FUNCTION [dbo].[IsValidCodeType]
(
#Code INT
)
RETURNS BIT
AS
BEGIN
DECLARE #Result BIT
IF EXISTS(SELECT * FROM dbo.Code WHERE CodeType = 0 AND Code = #Code)
SET #Result = 1
ELSE
SET #Result = 0
RETURN #Result
END
GO
One issue that has been raised is how to ensure that a table with a code column has a proper value for that code type. This too could be enforced by a check constraint using a function.
Here is a Person table which has a gender column. It could be a best practice to name all code columns with the description of the code type (Gender in this example) followed by the word Code:
CREATE TABLE [dbo].[Person](
[PersonID] [int] IDENTITY(1,1) NOT NULL,
[LastName] [nvarchar](40) NULL,
[FirstName] [nvarchar](40) NULL,
[GenderCode] [int] NULL,
CONSTRAINT [PK_Person] PRIMARY KEY CLUSTERED ([PersonID] ASC)
GO
ALTER TABLE [dbo].[Person] WITH CHECK ADD CONSTRAINT [CK_Person_GenderCode]
CHECK (([dbo].[IsValidCode]('Gender',[Gendercode])=(1)))
GO
IsValidCode could be defined this way:
CREATE FUNCTION [dbo].[IsValidCode]
(
#CodeTypeDescription NVARCHAR(40),
#Code INT
)
RETURNS BIT
AS
BEGIN
DECLARE #CodeType INT
DECLARE #Result BIT
SELECT #CodeType = Code
FROM dbo.Code
WHERE CodeType = 0 AND CodeDescription = #CodeTypeDescription
IF (#CodeType IS NULL)
BEGIN
SET #Result = 0
END
ELSE
BEGiN
IF EXISTS(SELECT * FROM dbo.Code WHERE CodeType = #CodeType AND Code = #Code)
SET #Result = 1
ELSE
SET #Result = 0
END
RETURN #Result
END
GO
Another function could be created to provide the code description when querying a table that has a code column. Here is an
example of querying the Person table:
SELECT PersonID,
LastName,
FirstName,
GetCodeDescription('Gender',GenderCode) AS Gender
FROM Person
This was all conceived from the perspective of preventing the proliferation of lookup tables in the database and providing one lookup table. I have no idea whether this design would perform well in practice.