I'm using the BulkExtensions library for EF Core. I have an object that contains a reference to another item example below
Child
public class Location
{
public string Id;
public string Description;
public string Item
}
Parent
public class Parent
{
public Guid Id;
public Location Location;
public string Name;
public string Service;
.....
}
I receive a list of Parent objects to add to my Postgres DB. I have the following code to add the items
List<Parent> parentObjects; // this is being passed in
var locations = _dbcontext.Locations().ToList();
foreach (var item in parentObjects)
{
item.Location = locations.First(x => x.Id == item.Location.Id);
// Additional logic
}
var bulkConfig = new BulkConfig()
{
//IncludeGraph = true,
CalculateStats = true,
PropertiesToIncludeOnUpdate = new List<string> { string.Empty }
};
await _dbContext.BulkInsertOrUpdateAsync(parentObjects, cancellationToken: cancellationToken,
bulkConfig: bulkConfig).ConfigureAwait(false);
await _dbContext.BulkSaveChangesAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
This adds the item to the table but the column for the foreign key locationId is always null. Is there configuration option that I am missing when calling the BulkInsertOrUpdate method?
If I add the IncludeGraph option for BuilkConfig, I get an exception that the Key is not found in the dictionary for the FK column.
Related
I have a database with several different, but related tables:
class AccountInfo {
string id;
string name;
string email;
}
class ExtraInfo {
string id;
string proxy;
}
class UserInfo {
AccountInfo account;
ExtraInfo extra;
}
public class MyDbContext : DbContext {
public DbSet<AccountInfo> AccountInfo { get; set; }
public DbSet<ExtraInfo> ExtraInfo { get; set; }
}
public class ExtraInfoController : ODataController
{
private readonly DS2DbContext _context;
private readonly ILogger<UserInfoController> _logger;
public ExtraInfoController(DS2DbContext context) {
_context = context;
}
[EnableQuery(PageSize = 15)]
public IQueryable<UserInfo> Get() {
IQueryable<UserInfo> query =
from a in _context.AccountInfo
from x in _context.ExtraInfo
where (a.id == x.id)
select new UserInfo() { account = a, extra = x };
return query;
}
The query in ExtraInfoController.Get() works, but the result cannot be transferred back to the calling code, because the DbSet is declared for type ExtraInfo and I guess because of the way Blazor mangles all the pseudo code passed to it into working code, so it expects the return type to be IQueryable and not IQeryable.
I am new to EF core, so I don't know how to create a controller that is not directly related to a db table that would do the desired join and return an IQueryable without there being a UserInfo table in the db.
I have a 1 to many relationship of Parent and Child to store some data. I want to store this data in PostgreSQL using Npgsql.EntityFrameworkCore.PostgreSQL package. Parent maps to a table, but Child is stored as a json column of Parent table in the database.
public class Parent
{
public int Id { get; set; }
[Column(TypeName = "json")]
public ICollection<Child> Children { get; set; }
}
public class Child
{
public int Id { get; set; }
public string Name { get; set; }
}
When I try to add a Child entity to an existing Parent instance with the code below, SaveChangesAsync doesn't produce an update command on the database.
var child = new Child(){Id = 0, Name = "Name"};
var parent = await DataContext.Parent.SingleOrDefaultAsync(f => f.Id == 1);
parent.Children.Add(child);
await DataContext.SaveChangesAsync();
In order to trigger an update command, I have to set parent entity's State to Modified before calling SaveChangesAsync.
var entry = DataContext.Entry<Parent>(parent);
entry.State = EntityState.Modified;
Is this the expected behavior or am I missing something?
Update:
As #SvyatoslavDanyliv suggested, instead of using ICollection when I use a class EqualityCollection derived from List and override Object.Equals as follows :
public class EqualityCollection<T> : List<T>
{
public override bool Equals(object? obj)
{
if (obj != null && obj.GetType() == typeof(EqualityCollection<T>))
return this.Equals(obj as EqualityCollection<T>);
return false;
}
public bool Equals(EqualityCollection<T> obj)
{
return this.SequenceEqual(obj ?? throw new InvalidOperationException());
}
public override int GetHashCode()
{
return base.GetHashCode();
}
}
Change detection doesn't detect the change in the property and update command is not triggered.
You have to define ValueComparer when defining conversion via HasConversion as described in documentation: Value Comparers
I'm using EclipseLink to run some Native SQL. I need to return the data into a POJO. I followed the instructions at EclipseLink Docs, but I receive the error Missing descriptor for [Class]
The query columns have been named to match the member variables of the POJO. Do I need to do some additional mapping?
POJO:
public class AnnouncementRecipientsFlattenedDTO {
private BigDecimal announcementId;
private String recipientAddress;
private String type;
public AnnouncementRecipientsFlattenedDTO() {
super();
}
public AnnouncementRecipientsFlattenedDTO(BigDecimal announcementId, String recipientAddress, String type) {
super();
this.announcementId = announcementId;
this.recipientAddress = recipientAddress;
this.type = type;
}
... Getters/Setters
Entity Manager call:
public List<AnnouncementRecipientsFlattenedDTO> getNormalizedRecipientsForAnnouncement(int announcementId) {
Query query = em.createNamedQuery(AnnouncementDeliveryLog.FIND_NORMALIZED_RECIPIENTS_FOR_ANNOUNCEMENT, AnnouncementRecipientsFlattenedDTO.class);
query.setParameter(1, announcementId);
return query.getResultList();
}
I found out you can put the results of a Native Query execution into a List of Arrays that hold Objects. Then one can iterate over the list and Array elements and build the desired Entity objects.
List<Object[]> rawResultList;
Query query =
em.createNamedQuery(AnnouncementDeliveryLog.FIND_NORMALIZED_RECIPIENTS_FOR_ANNOUNCEMENT);
rawResultList = query.getResultList();
for (Object[] resultElement : rawResultList) {
AnnouncementDeliveryLog adl = new AnnouncementDeliveryLog(getAnnouncementById(announcementId), (String)resultElement[1], (String)resultElement[2], "TO_SEND");
persistAnnouncementDeliveryLog(adl);
}
You can only use native SQL queries with a class if the class is mapped. You need to define the AnnouncementRecipientsFlattenedDTO class as an #Entity.
Otherwise just create the native query with only the SQL and get an array of the data back and construct your DTO yourself using the data.
Old question but may be following solution will help someone else.
Suppose you want to return a list of columns, data type and data length for a given table in Oracle. I have written below a native sample query for this:
private static final String TABLE_COLUMNS = "select utc.COLUMN_NAME, utc.DATA_TYPE, utc.DATA_LENGTH "
+ "from user_tab_columns utc "
+ "where utc.table_name = ? "
+ "order by utc.column_name asc";
Now the requirement is to construct a list of POJO from the result of above query.
Define TableColumn entity class as below:
#Entity
public class TableColumn implements Serializable {
#Id
#Column(name = "COLUMN_NAME")
private String columnName;
#Column(name = "DATA_TYPE")
private String dataType;
#Column(name = "DATA_LENGTH")
private int dataLength;
public String getColumnName() {
return columnName;
}
public void setColumnName(String columnName) {
this.columnName = columnName;
}
public String getDataType() {
return dataType;
}
public void setDataType(String dataType) {
this.dataType = dataType;
}
public int getDataLength() {
return dataLength;
}
public void setDataLength(int dataLength) {
this.dataLength = dataLength;
}
public TableColumn(String columnName, String dataType, int dataLength) {
this.columnName = columnName;
this.dataType = dataType;
this.dataLength = dataLength;
}
public TableColumn(String columnName) {
this.columnName = columnName;
}
public TableColumn() {
}
#Override
public int hashCode() {
int hash = 0;
hash += (columnName != null ? columnName.hashCode() : 0);
return hash;
}
#Override
public boolean equals(Object object) {
if (!(object instanceof TableColumn)) {
return false;
}
TableColumn other = (TableColumn) object;
if ((this.columnName == null && other.columnName != null) || (this.columnName != null && !this.columnName.equals(other.columnName))) {
return false;
}
return true;
}
#Override
public String toString() {
return getColumnName();
}
}
Now we are ready to construct a list of POJO. Use the sample code below to construct get your result as List of POJOs.
public List<TableColumn> findTableColumns(String table) {
List<TableColumn> listTables = new ArrayList<>();
EntityManager em = emf.createEntityManager();
Query q = em.createNativeQuery(TABLE_COLUMNS, TableColumn.class).setParameter(1, table);
listTables = q.getResultList();
em.close();
return listTables;
}
Also, don't forget to add in your POJO class in persistence.xml! It can be easy to overlook if you are used to your IDE managing that file for you.
Had the same kind of problem where I wanted to return a List of POJOs, and really just POJOs (call it DTO if you want) and not #Entity annotated Objects.
class PojoExample {
String name;
#Enumerated(EnumType.STRING)
SomeEnum type;
public PojoExample(String name, SomeEnum type) {
this.name = name;
this.type = type;
}
}
With the following Query:
String query = "SELECT b.name, a.newtype as type FROM tablea a, tableb b where a.tableb_id = b_id";
Query query = getEntityManager().createNativeQuery(query, "PojoExample");
#SuppressWarnings("unchecked")
List<PojoExample> data = query.getResultList();
Creates the PojoExample from the database without the need for an Entity annotation on PojoExample. You can find the method call in the Oracle Docs here.
edit:
As it turns out you have to use #SqlResultSetMapping for this to work, otherwise your query.getResultList() returns a List of Object.
#SqlResultSetMapping(name = "PojoExample",
classes = #ConstructorResult(columns = {
#ColumnResult(name = "name", type = String.class),
#ColumnResult(name = "type", type = String.class)
},
targetClass = PojoExample.class)
)
Just put this anywhere under your #Entity annotation (so in this example either in tablea or tableb because PojoExample has no #Entity annotation)
I am using tje JPA criteria API to create an "IN" query. I want to select Courses that are in certain Categories. The Categories are supposed to end up in the IN part of the query.
This is the Course entity. It has a reference to a Category entity, because each Course is in one Category.
#Entity
public class Course implements DomainObject {
private Long id;
private Integer version;
private String name;
private Category category;
#Override
#Id
#GeneratedValue
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
#ManyToOne
public Category getCategory() {
return category;
}
public void setCategory(Category category) {
this.category = category;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getVersion() {
return version;
}
public void setVersion(Integer version) {
this.version = version;
}
}
In my service I want to select Courses that are belong to certain (a list) of Categories.
public List<Course> findCourses(CourseFilter filter) {
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<Course> criteriaQuery = criteriaBuilder.createQuery(Course.class);
Root<Course> root = criteriaQuery.from(Course.class);
List<Predicate> predicateList = new ArrayList<Predicate>();
if (!filter.getCategories().isEmpty()) {
Predicate predicate = root.get(Course_.category).in(filter.getCategories());
predicateList.add(predicate);
}
Predicate[] predicates = new Predicate[predicateList.size()];
predicateList.toArray(predicates);
criteriaQuery.where(predicates);
TypedQuery<Course> typedQuery = entityManager.createQuery(criteriaQuery);
return typedQuery.getResultList();
}
When the query executes on the last line of the method it throws an error:
HTTP Status 500 - Request processing failed; nested exception is
org.springframework.dao.InvalidDataAccessApiUsageException:
org.hibernate.TransientObjectException: object references an unsaved transient instance
save the transient instance before flushing:nl.codebasesoftware.produx.domain.Category;
nested exception is java.lang.IllegalStateException:
org.hibernate.TransientObjectException: object references an unsaved transient instance
save the transient instance before flushing: nl.codebasesoftware.produx.domain.Category
I am not even sure I am using the right way to create an IN query. I think the criteria API is terribly complicated. But before I worry about the IN query I would like to know why Hibernate is throwing this TransientObjectException. The filter.getCategories() call results in actual categories, filled with a primary key id, etc.
Added:
Here is how I get the Category instance that I use to later fetch Courses with. This is also a DAO method that is called via a #Service from a #Controller method.
public Category findByName(String name) {
CriteriaBuilder builder = entityManager.getCriteriaBuilder();
CriteriaQuery<Category> query = builder.createQuery(Category.class);
Root<Category> root = query.from(Category.class);
Predicate predicate = builder.equal(root.get(Category_.urlTitle), name);
query.where(predicate);
TypedQuery<Category> typedQuery = entityManager.createQuery(query);
return getSingleResult(typedQuery);
}
So, Hibernate is telling me I am using Category objects that somehow reference an unsaved entity, but I don't see how. The Category that is returned from this method is just a Category that if fetched by Hibernate. I am not doing anything with it before I send it to the method that fetches Courses.
Here is my the controller method:
#RequestMapping(method = RequestMethod.GET, value = "/{categoryUrlName}")
public String setup(#PathVariable("categoryUrlName") String categoryUrlName, Model model){
// Fetch the category
Category category = categoryService.findByName(categoryUrlName);
// if no category found, throw a 404
if(category == null){
throw new ResourceNotFoundException();
}
// Fetch courses in this category
List<Course> courses = courseService.findCourses(category);
model.addAttribute("courses", courses);
model.addAttribute("category", category);
model.addAttribute("mainContent", "content/category");
return "main";
}
Before executing a query, Hibernate flushes the changes you made to persistent entities in the session. This ensures that the query will search on the latest state of all the entities. Unfortunately, one of the dirty entities that Hibernate tries to flush references a transient entity, and thus can't be flushed, which causes the exception. The exception doesn't come from the query itself, but from the flush before the execution of the query.
You probably did something like the following before executing the query:
Cat cat = em.find(Cat.class, catId); // cat is a persistent persistent entity
cat.setMate(new Mouse()); // the mouse has not been persisted, and cat references it.
I'd like to define an enum for EF5 to use, and a corresponding lookup table. I know EF5 now supports enums, but out-of-the-box, it seems it only supports this at the object level, and does not by default add a table for these lookup values.
For example, I have a User entity:
public class User
{
int Id { get; set; }
string Name { get; set; }
UserType UserType { get; set; }
}
And a UserType enum:
public enum UserType
{
Member = 1,
Moderator = 2,
Administrator = 3
}
I would like for database generation to create a table, something like:
create table UserType
(
Id int,
Name nvarchar(max)
)
Is this possible?
Here's a nuget package I made earlier that generates lookup tables and applies foreign keys, and keeps the lookup table rows in sync with the enum:
https://www.nuget.org/packages/ef-enum-to-lookup
Add that to your project and call the Apply method.
Documentation on github: https://github.com/timabell/ef-enum-to-lookup
It is not directly possible. EF supports enums on the same level as .NET so enum value is just named integer => enum property in class is always integer column in the database. If you want to have table as well you need to create it manually in your own database initializer together with foreign key in User and fill it with enum values.
I made some proposal on user voice to allow more complex mappings. If you find it useful you can vote for the proposal.
I wrote a little helper class, that creates a database table for the enums specified in the UserEntities class. It also creates a foreign key on the tables that referencing the enum.
So here it is:
public class EntityHelper
{
public static void Seed(DbContext context)
{
var contextProperties = context.GetType().GetProperties();
List<PropertyInfo> enumSets = contextProperties.Where(p =>IsSubclassOfRawGeneric(typeof(EnumSet<>),p.PropertyType)).ToList();
foreach (var enumType in enumSets)
{
var referencingTpyes = GetReferencingTypes(enumType, contextProperties);
CreateEnumTable(enumType, referencingTpyes, context);
}
}
private static void CreateEnumTable(PropertyInfo enumProperty, List<PropertyInfo> referencingTypes, DbContext context)
{
var enumType = enumProperty.PropertyType.GetGenericArguments()[0];
//create table
var command = string.Format(
"CREATE TABLE {0} ([Id] [int] NOT NULL,[Value] [varchar](50) NOT NULL,CONSTRAINT pk_{0}_Id PRIMARY KEY (Id));", enumType.Name);
context.Database.ExecuteSqlCommand(command);
//insert value
foreach (var enumvalue in Enum.GetValues(enumType))
{
command = string.Format("INSERT INTO {0} VALUES({1},'{2}');", enumType.Name, (int)enumvalue,
enumvalue);
context.Database.ExecuteSqlCommand(command);
}
//foreign keys
foreach (var referencingType in referencingTypes)
{
var tableType = referencingType.PropertyType.GetGenericArguments()[0];
foreach (var propertyInfo in tableType.GetProperties())
{
if (propertyInfo.PropertyType == enumType)
{
var command2 = string.Format("ALTER TABLE {0} WITH CHECK ADD CONSTRAINT [FK_{0}_{1}] FOREIGN KEY({2}) REFERENCES {1}([Id])",
tableType.Name, enumProperty.Name, propertyInfo.Name
);
context.Database.ExecuteSqlCommand(command2);
}
}
}
}
private static List<PropertyInfo> GetReferencingTypes(PropertyInfo enumProperty, IEnumerable<PropertyInfo> contextProperties)
{
var result = new List<PropertyInfo>();
var enumType = enumProperty.PropertyType.GetGenericArguments()[0];
foreach (var contextProperty in contextProperties)
{
if (IsSubclassOfRawGeneric(typeof(DbSet<>), contextProperty.PropertyType))
{
var tableType = contextProperty.PropertyType.GetGenericArguments()[0];
foreach (var propertyInfo in tableType.GetProperties())
{
if (propertyInfo.PropertyType == enumType)
result.Add(contextProperty);
}
}
}
return result;
}
private static bool IsSubclassOfRawGeneric(Type generic, Type toCheck)
{
while (toCheck != null && toCheck != typeof(object))
{
var cur = toCheck.IsGenericType ? toCheck.GetGenericTypeDefinition() : toCheck;
if (generic == cur)
{
return true;
}
toCheck = toCheck.BaseType;
}
return false;
}
public class EnumSet<T>
{
}
}
using the code:
public partial class UserEntities : DbContext{
public DbSet<User> User { get; set; }
public EntityHelper.EnumSet<UserType> UserType { get; set; }
public static void CreateDatabase(){
using (var db = new UserEntities()){
db.Database.CreateIfNotExists();
db.Database.Initialize(true);
EntityHelper.Seed(db);
}
}
}
I have created a package for it
https://www.nuget.org/packages/SSW.Data.EF.Enums/1.0.0
Use
EnumTableGenerator.Run("your object context", "assembly that contains enums");
"your object context" - is your EntityFramework DbContext
"assembly that contains enums" - an assembly that contains your enums
Call EnumTableGenerator.Run as part of your seed function. This will create tables in sql server for each Enum and populate it with correct data.
I have included this answer as I've made some additional changes from #HerrKater
I made a small addition to Herr Kater's Answer (also based on Tim Abell's comment). The update is to use a method to get the enum value from the DisplayName Attribute if exists else split the PascalCase enum value.
private static string GetDisplayValue(object value)
{
var fieldInfo = value.GetType().GetField(value.ToString());
var descriptionAttributes = fieldInfo.GetCustomAttributes(
typeof(DisplayAttribute), false) as DisplayAttribute[];
if (descriptionAttributes == null) return string.Empty;
return (descriptionAttributes.Length > 0)
? descriptionAttributes[0].Name
: System.Text.RegularExpressions.Regex.Replace(value.ToString(), "([a-z](?=[A-Z])|[A-Z](?=[A-Z][a-z]))", "$1 ");
}
Update Herr Katers example to call the method:
command = string.Format("INSERT INTO {0} VALUES({1},'{2}');", enumType.Name, (int)enumvalue,
GetDisplayValue(enumvalue));
Enum Example
public enum PaymentMethod
{
[Display(Name = "Credit Card")]
CreditCard = 1,
[Display(Name = "Direct Debit")]
DirectDebit = 2
}
you must customize your workflow of generation
1. Copy your default template of generation TablePerTypeStrategy
Location : \Microsoft Visual Studio 10.0\Common7\IDE\Extensions\Microsoft\Entity Framework Tools\DBGen.
2. Add custom activity who realize your need (Workflow Foundation)
3. Modify your section Database Generation Workflow in your project EF