I am new to Hibernate. Now I have a problem. I have 2 tables (Timetable, and Timetable_backup) with similar structure because the timetable_backup table is just back up version of timetable table which contains current data. Now I do not know how to get all data from the past to now. In hibernate, we cannot use UNION like in SQL to query. So I try to map 2 tables to 1 entity using Inheritance and #mappedsuperclass but it does not work for me. Please help me with this. If the context is not clear please tell me.
Kind Regards
Nathan
Probably what you want is something like Envers, a plugin for Hibernate that takes care of versioning records in a table. You just use a couple of annotations in your classes and it provides an interface to look for past records among other things.
You cannot do it.
The typical workaround is to map entity to the main table, and use native SQL queries to access the backup table.
By this time you might have found answer or workaround to the problem you have posted. If possible, can you please post it here so that it will help others.
Anyway I found following link which explains how to create tables using single POJO Mapping same POJO to more than one table in Hibernate.
As hibernate does not support union. I have extracted results from 2 queried (main table as well as backup table) and used listTimeTable.addAll(listbackTimeTable); This will give result same as union all operation.
Once again, please post your implementation for benefit of this community...
Thanks,
Shirish
Related
I'm following a tutorial on Azure Data Factory migration from Azure SQL to Blob through pipelines. While most of the concepts make sense, the 'Copy Data' query is a bit confusing. I have a background in writing Oracle SQL, but Azure SQL on ADF is pretty different and I'm struggling to find specific technical documentation, probably because it's not widely adopted yet.
Pipeline configuration shown below:
Query is posted below:
SELECT data_source_table.PersonID,data_source_table.Name,data_source_table.Age,
CT.SYS_CHANGE_VERSION, SYS_CHANGE_OPERATION
FROM data_source_table
RIGHT OUTER JOIN CHANGETABLE(CHANGES data_source_table,
#{activity('LookupLastChangeTrackingVersionActivity').output.firstRow.SYS_CHANGE_VERSION})
AS CT ON data_source_table.PersonID = CT.PersonID
WHERE CT.SYS_CHANGE_VERSION <=
#{activity('LookupCurrentChangeTrackingVersionActivity').output.firstRow.CurrentChangeTrackingVersion}
Output to the sink Blob as a result of the 'Copy Data' query:
2,name2,14,4,U
7,name7,51,3,I
8,name8,31,5,I
9,name9,38,6,I
Couple questions I had:
There's a lot of external referencing from other activities in the 'Copy Data' query like #{activity('...').output.firstRow.CurrentChangeTrackingVersion. Is there a way to know the appropriate syntax to referencing external activities? Can't find any good documentation the syntax, like what .firstRow is or what the changetable output looks like. I can't replicate this query in SSMS, which makes it a bit of a black box for me.
SYS_CHANGE_OPERATION appears in the SELECT with no table name prefix. Is this directly querying from the table in SourceDataset? (It points to data_source_table, which has table tracking enabled) My main confusion stems from how table tracking information is stored in the enabled tables. Is there a way to show all the table's tracked changes in SSMS? I see some documentation on what the return values, but it's hard for me to visualize it without seeing it on the table, so an output query of some return values would be nice.
LookupLastChangeTracking activity queries in all rows from a table (which when I checked, is just one row), but LookupCurrentChangeTracking activity uses a CHANGE_TRACKING function to pull the version of the data sink in table_store_ChangeTracking_version. Why does it use a function when the data sink's version is already recorded in table_store_ChangeTracking_version?
Sorry for the many questions, but I can't find any way to make this learning curve a bit less steep. Any guides or resources would be awesome!
There is an article to get the same thing done from the UI and it will help you understand it better .
https://learn.microsoft.com/en-us/azure/data-factory/tutorial-incremental-copy-change-tracking-feature-portal .
1 . These are the Lookup activity ,. very straight forward , please read about them here .
https://learn.microsoft.com/en-us/azure/data-factory/control-flow-lookup-activity
2.SYS_CHANGE_OPERATION is a column on data_source_table and so that should be fine . Regarding the details on the how the change tracking (CT) is stored , I am not sure if all the system table are exposed on Azure SQL , but we did had few table on the on-prem version of the SQL which could be queried if needed . But for this exercise I think that will be an over kill .
I am new to SQL Server, coming from a MySQL background. I am trying to migrate a MySQL table that contains several fields defined similarly to the following one:
"FavoriteColors" SET('Red','Blue','Dark Purple', 'Green') DEFAULT NULL,
Basically, they are multiple-choice questions. When entering these fields in a form, the user will be able to select one or more of them.
When looking for a SQL Server equivalent to this definition, I have seen that many people create an extra table for the different choices, and then a lookup table to connect the two previous ones. Knowing that there are several multiple-choice fields like this one, it seems a pretty complicated solution for such a simple definition. Is this really best practices, or do you recommend an alternate solution? Of course, I can use BIT fields for each of the choices, but again, it seems to me that SQL Server probably has a simpler, better organized solution for this.
Thanks a lot!
You can create user-defined type and create a rule for this data type. This enables you use this new data type everywhere in your database
Here is the code, please execute step by step
CREATE TYPE [dbo].[Color] FROM [nvarchar](40) NULL
CREATE RULE ruleColor
AS
(#phone='Red') OR
(#phone='Black')
GO
EXEC sp_bindrule 'ruleColor', 'Color'
I hope it helps,
I want to make a site in which every user has his own customers and products to manage.
Whats the best way to handle this??
Is it OK to use an additional field for each entry specifying the user this entry belongs to ? or there is a better way?
Im using sql server if it matters.
Thank You.
not really much info in the question... however:
it is much simpler to scale some more data in a single database than to create additional databases. so YES - make one database.
the exact schema you choose is more subtle - normalize, and link rows to appropriate users
Do NOT I repeat do NOT create a database per user, not even a table per user.
Add a column UserID to any table that may need to reference a person with a product or order.
First of all before I get into the question, I'll preface this with the fact that I know that this is a "bad" idea. But for business reasons it is something that I have to come up with a solution to, and I'm hoping that someone, somewhere might have some ideas on how to go about this.
I have a SQL Server 2008 R2 table that has a "OtherProperties" column. This column contains various other, somewhat arbitrary additional pieces of information that relate to the records. There is a business need to create a UDF that we can use to query the results, for example.
SELECT *
FROM MyTable
WHERE MyUDFGetValue(myTable.OtherProperties, "LinkedOrder[0]") IS NOT NULL
This would find a record where there was an array of LinkedOrder entries that contained a value at index 0
SELECT *
FROM MyTable
WHERE MyUDFGetValue(myTable.OtherProperties, "SubOrder.OrderId") = 25
This would find a property "orderId" and use its value in a comparison.
Anyone seen an implementation of this? I've seen implementations of functions. Like this JSONParser that take the values into a table which just will not get us what we need query wise. Complexity wise, I don't want to write a full fledged JSON parser, but I can if I need to.
Not sure if this will suit your needs but I read about a CLR JSON serializer/deserializer. You can find it here, http://www.sqlservercentral.com/articles/CLR/74160/
It's been a long time since you asked your question but there is now a solution you can use - JSON Select which provides various functions for different datatypes, for example the JsonInt() function. From one of your examples (assuming OrderId is an int, if not you could use a different function):
SELECT *
FROM MyTable
WHERE dbo.JsonInt(myTable.OtherProperties, 'SubOrder.OrderId') = 25
DISCLOSURE:
I am the author of JSON Select, and as such have an interest in you using it :)
If you cannot use SQL Server 2016 with built-in JSON support, you would need to use CLR e.g. JSONselect, json4sql, or custom code such as http://www.codeproject.com/Articles/1000953/JSON-for-SQL-Server-Part, etc.
I've just started using Subsonic 2.2 and so far very impressed - think it'll save me some serious coding time.
Before I dive into using it full time though there is something bugging me that I'd like to sort out.
In my current database (a SQL2008 db) I have split the tables, views, sps etc. up into separate chunks by schema/owner name, so all the customer tables are in the customer. schema, products in the product. schema etc., so a to select from the customers address table i'd do a select * from customer.address
Unfortunately, Subsonic ignores the schema/owner name and just gives me the base table name. This is fine as I've no duplicates between schemas (e.g Customer.Address and Supplier.Address don't both exist) but I just feel the code could be clearer if I could split by schema.
Ideally I'd like to be able to alter the namespace by schema/owner - I think this would have least impact on SubSonic yet make the resulting code easier to read.
Problem is, I've crawled all over the Subsonic source and don't have a clue how to do this (doesn't help that I code in VB not C# = yes I know, blame the ZX Spectrum!!)
If anyone has tackled this before or has an idea on how to solve it, I'd be really grateful,
Thanks in advance.
Ed
I was going to suggest the multiple provider approach too.
But a lot of the plumbing is already in subsonic for ownership.
If you edit a couple of lines in CS_ClassTemplate.aspx you can create a namespace for each owner profile. Change around line 58 (I'm using v2.1) to
namespace <%=provider.GeneratedNamespace%><%=owner%>
where owner is
string owner = "." + tbl.SchemaName;
if(owner == ".dbo")
owner = "";
You put that up above, around line 14. This way you can have a namespace for every owner like:
Northwind.Suppliers, Northwind.Customers, etc.
I left dbo as just Northwind so all the tests would compile without a lot of editing.
I ran a simple select query and I think it will work the way you want.
You could do this in 3.0 as well using our t4 templates (but it's 3.5 only). This is a really good bit of feedback - we should build this in by default perhaps!
Glad you got some help here.
Just to let you know I have this now working - or at least, compiling! :-) To get the owner solution to work fully though you'll need to make more changes to the Class Template as otherwise the table/key functions sit within the wrong namespace.
I've also hacked around with the stored procedure template. I couldn't (in the short time I have) work out how to split into separate files/namespaces for each owner so instead i've prefixed each sp function with the owner and an underscore.
However, just in case you have the same problem you'll know its possible to fix.
Ed
You could try doing separate providers that have the same underlying database connection, like so:
<SubSonicService defaultProvider="DBData">
<providers>
<clear/>
<add name="DBData" type="Subsonic.SqlDataProvider, SubSonic" connectionStringName="LocalSqlServer" generatedNamespace="DBData" includeTableList="table_a,table_b" spStartsWith="app,get,set" viewStartsWith="v_" />
<!--CMS Provider-->
<add name="CMS" type="SubSonic.SqlDataProvider, SubSonic" connectionStringName="LocalSqlServer" generatedNamespace="CMS" stripTableText="CMS_" includeTableList="CMS_Content,CMS_Page" useSPs="false"/>
</providers>
</SubSonicService>
I don't think you can use the schema itself as a key in this way, but you could at least work around the issue with a combination of includeTableList and generatedNamespace. You said that you don't have duplicate table names across the different schemas, so it just might work.