Is it possible to define dynamic schema with OrmLite in runtime. For instance, when reading object through OrmLite is it possible to define which schema to read it from.
This would be best shown through an example. Let's say I have 3 User tables inside MSSQL 2008 R2 database:
Schema1.user
Schema2.User
Schema3.User
I have an object User with some properties defined. I select data like this "db.Select();". The problem is I have not defined from which schema to read User data from. I want to be able to do this at runtime, but I can't seem to find a propert way to do it.
Using C#, .NET 4.5 fw, MSSQL 2008 R2 Database
Thank you!
You can do this by modifying OrmLite's metadata that it maintains for each type, i.e:
var modelDef = SqlServerOrmLiteDialectProvider.GetModelDefinition(typeof(Poco));
var existingSchema = modelDef.Schema;
modelDef.Schema = "Schema2";
// All queries on Poco now use `Schema2`
modelDef.Schema = existingSchema; //Retain existing behavior
This functionality has gotten easier in the current release. You can just do data annotations over the class to set the as is explained here.
example:
[Schema("test")]
public class Foo
{
}
Related
I have a Cosmos DB with a container that contains document with varying structure.
I am using the Java SQL API for reading the documents from this container.
The issue I am having is that the API methods for querying/reading the container expects a model class as input param and will return instances of the model class. Because my container contains documents that have varying fields and depth, it is not possible for me to create a model class to represent this.
I need to be able to read/query the documents and then parse it myself and extract the values that I am looking for.
Any ideas? I have used "Object" in the API methods for e.g. queryItem and then it returns a LinkedHashMap that I can parse myself. Is this the way to do it? It looks a bit "raw" but I have not found a better way.
Below is a typical example from the SDK doc. I cannot create a "Family" model class in my code, because the structure can vary from document to document - both which fields are stored and the depth.
private void queryItems() {
CosmosQueryRequestOptions queryOptions = new CosmosQueryRequestOptions();
queryOptions.setQueryMetricsEnabled(true);
CosmosPagedIterable<Family> familiesPagedIterable = container.queryItems(
"SELECT * FROM Family WHERE Family.lastName IN ('Andersen', 'Wakefield', 'Johnson')", queryOptions, Family.class);
familiesPagedIterable.iterableByPage(10).forEach(cosmosItemPropertiesFeedResponse -> {
logger.info("Got a page of query result with {} items(s) and request charge of {}",
cosmosItemPropertiesFeedResponse.getResults().size(), cosmosItemPropertiesFeedResponse.getRequestCharge());
logger.info("Item Ids {}", cosmosItemPropertiesFeedResponse
.getResults()
.stream()
.map(Family::getId)
.collect(Collectors.toList()));
});
}
Per my understanding, it's determined by the sdk funtion's input parameters and output data type. And exactly, we can find that both sample code for java or spring are depends on the data model. So it's really good for you to use Object in your code because of the various documents.
And it's true that we can't design a data model to contain all the properties in the documents but I think it's also a good idea to set a model which contains all the properties required. I mean that maybe you have a useless property in a query, so the query model should exclude it.
I think I found the proper solution:
Create model class. Define the members with unknown depth and structure as JsonNode.
Then the model class could be used and the values of the JsonNode accessed using nice methods.
I've following requirement:
During the model configuration, I create a QueryFilter for an Entity
var entity = modelBuilder.Entity<TBaseTable>().HasQueryFilter(r => r.UserId == CurrentUserId)
So during runtime in some cases the CurrentUserId changes. But my QueryFilter does not get refreshed. The filter criteria still are working with the old UserId value, which I had during the configuration. How do i modify the my QueryFiler, which was set during the configuration? If I'm right then the whole model is already cached and will not be reinitialized. Any ideas about that?
The trick is to declare CurrentUserId as a property on your DbContext class - the property getter can still return a value from a global class instance.
Global filters can be made dynamic by using properties/methods/fields of the db context. See the TenantId example in Global Query Filters documentation.
(Since I needed to read the comments to find the answer to your question I rephrased the comment as provided by "Ivan Stoev Oct 8 '19 at 15:34" and posted it as an answer)
Is there a way we can use ObjectContext with DbContext's ModelBuilder? We don't want to use POCO because we have customized property code that does not modify entire object in update, but only update modified properties. Also we have lots of serialisation and auditing code that uses EntityObject.
Since poco does create a proxy with EntityObject, we want our classes to be derived from EntityObject. We don't want proxy. We also heavily use CreateSourceQuery. The only problem is EDMX file and its big connection string syntax web.config.
Is there any way I can get rid of EDMX file? It will be useful as we can dynamically compile new class based on reverse engineering database.
I would also like to use DbContext with EntityObject instead of poco.
Internal Logic
Access Modified Properties in Save Changes which is available in ObjectStateEntry and Save them onto Audit with Old and New Values
Most of times we need to only check for Any condition on Navigation Property for example
User.EmailAddresses.CreateSourceQuery()
.Any( x=> x.EmailAddress == givenAddress);
Access Property Attributes, such as XmlIgnore etc, we rely heavily on attributes defined on the properties.
A proxy for a POCO is a dynamically created class which derives from (inherits) a POCO. It adds functionality previously found in EntityObject, namely lazy loading and change tracking, as long as a POCO meets requirements. A POCO or its proxy does not contain an EntityObject as the question suggests, but rather a proxy contains functionality of EntityObject. You cannot (AFAIK) use ModelBuilder with EntityObject derivatives and you cannot get to an underlying EntityObject from a POCO or a proxy, since there isn't one as such.
I don't know what features of ObjectContext does your existing serialisation and auditing code use, but you can get to ObjectContext from a DbContext by casting a DbContext to a IObjectContextAdapter and accessing IObjectContextAdapter.ObjectContext property.
EDIT:
1. Access Modified Properties in Save Changes which is available in ObjectStateEntry and Save them onto Audit with Old and New Values
You can achieve this with POCOs by using DbContext.ChangeTracker. First you call DbContext.ChangeTracker.DetectChanges to detect the changes (if you use proxies this is not needed, but can't hurt) and then you use DbCotnext.Entries.Where(e => e.State != EntityState.Unchanged && e.State != EntityState.Detached) to get DbEntityEntry list of changed entities for auditing. Each DbEntityEntry has OriginalValues and CurrentValues and the actual Entity is in property Entity.
You also have access to ObjectStateEntry, see below.
2. Most of times we need to only check for Any condition on Navigation Property for example:
User.EmailAddresses.CreateSourceQuery().Any( x=> x.EmailAddress == givenAddress);
You can use CreateSourceQuery() with DbContext by utilizing IObjectContextAdapter as described previously. When you have ObjectContext you can get to the source query for a related end like this:
public static class DbContextUtils
{
public static ObjectQuery<TMember> CreateSourceQuery<TEntity, TMember>(this IObjectContextAdapter adapter, TEntity entity, Expression<Func<TEntity, ICollection<TMember>>> memberSelector) where TMember : class
{
var objectStateManager = adapter.ObjectContext.ObjectStateManager;
var objectStateEntry = objectStateManager.GetObjectStateEntry(entity);
var relationshipManager = objectStateManager.GetRelationshipManager(entity);
var entityType = (EntityType)objectStateEntry.EntitySet.ElementType;
var navigationProperty = entityType.NavigationProperties[(memberSelector.Body as MemberExpression).Member.Name];
var relatedEnd = relationshipManager.GetRelatedEnd(navigationProperty.RelationshipType.FullName, navigationProperty.ToEndMember.Name);
return ((EntityCollection<TMember>)relatedEnd).CreateSourceQuery();
}
}
This method uses no dynamic code and is strongly typed since it uses expressions. You use it like this:
myDbContext.CreateSourceQuery(invoice, i => i.details);
I need to query a table using FreeTextTable (because I need ranking), with SubSonic. AFAIK, Subsonic doesn't support FullText, so I ended up creating a simple UDF function (Table Function) which takes 2 params (keywords to search and max number of results).
Now, how can I inner join the main table with this FreeTextTable?
InlineQuery is not an option.
Example:
table ARTICLE with fields Id, ArticleName, Author, ArticleStatus.
The search can be done by one of more of the following fields: ArticleName (fulltext), Author (another FullText but with different search keywords), ArticleStatus (an int).
Actually the query is far more complex and has other joins (depending on user choice).
If SubSonic cannot handle this situation, probably the best solution is good old plain sql (so there would be no need to create an UDF, too).
Thanks for your help
ps: will SubSonic 3.0 handle this situation?
3.0 can do this for you but you'd need to make a template for it since we don't handle functions (yet) out of the box. I'll be working on this in the coming weeks - for now I don't think 2.2 will do this for you.
I realize your question is more complex than this, but you can get results from a table valued function via SubSonic 2.2 with a little massaging.
Copy the .cs file from one of your generated views into a safe folder, and then change all the properties to match the columns returned by your UDF.
Then, on your collection, add a constructor method with your parameters and have it execute an InlineQuery.
public partial class UDFSearchCollection
{
public UDFSearchCollection(){}
public UDFSearchCollection(string keyword, int maxResults)
{
UDFSearchCollection coll = new InlineQuery().ExecuteAsCollection<UDFSearchCollection>("select resultID, resultColumn from dbo.udfSearch(#keyword, #maxResults)",keyword,maxResults);
coll.CopyTo(this);
coll = null;
}
}
public partial class UDFSearch : ReadOnlyRecord<UDFSearch>, IReadOnlyRecord
{
//all the methods for read only record go here
...
}
An inner join would be a little more difficult because the table object doesn't have it's own parameters collection. But it could...
It could very well be that I'm just missing the correct vernacular in this space, but I'm looking for a particular piece of functionality in SubSonic. In NetTiers it was called a "DeepLoad". A deep load runs to the database and fetches many objects (ie. fetch this OrderDetail and all of it's LineItems) in one database call.
Again, I want to run to the data store once an build up a potentially dense object graph or related items populated by the data store.
How do I do this in SubSonic and what is it called in SubSonic?
You can do this in SubSonic 3.0 (not yet released, but almost there...) using IQueryable with lazy loading:
var db=new NorthwindDB();
var order=db.Orders.Where(x=>.xID==20).SingleOrDefault();
Assert.Equal(3,order.OrderDetails.Count());
if you're not on 3 (which requires .net 3.5) you can do this with Active record as Paul mentions - but it will make two calls.
There is no eager loading, and DeepSave in ActiveRecord only calls Save.
Here is an example with Northwind Order class foreign key method.
[Test]
public void SelectOrderDetails()
{
Order order = new Order(10250);
OrderDetailCollection details = order.OrderDetails();
Assert.IsTrue(details.Count == 3);
}