I'm trying to make two 1:1 relations in one model in Prisma ORM, but got following error:
Error validating model "Person": Ambiguous relation detected. The fields placeOfBirth and placeOfDeath in model Person both refer to Place. Please provide different relation names for them by adding #relation(<name>).
My prisma schema:
model Place {
id Int #id #default(autoincrement())
name String
persons Person[]
}
model Person {
id Int #id #default(autoincrement())
name String
placeOfBirthId Int
placeOfDeathId Int
👉 placeOfBirth Place #relation(fields: [placeOfBirthId], references: [id])
placeOfDeath Place #relation(fields: [placeOfDeathId], references: [id])
}
Totally don't get it.
You have to add a name field to placeOfBirth and placeOfDeath. Then use these names to reference both of them in the Place model.
model Place {
id Int #id #default(autoincrement())
name String
Births Person[] #relation("Births")
Deaths Person[] #relation("Deaths")
}
model Person {
id Int #id #default(autoincrement())
name String
placeOfBirthId Int
placeOfDeathId Int
placeOfBirth Place #relation("Births", fields: [placeOfBirthId], references: [id])
placeOfDeath Place #relation("Deaths", fields: [placeOfDeathId], references: [id])
}
Related
This is a default structure of prisma schema...
generator client {
provider = "prisma-client-js"
}
datasource db {
provider = "mysql"
url = env("DATABASE_URL")
}
model User {
id Int #id #default(autoincrement())
username String #unique #db.VarChar(255)
role UserRole #default(admin)
posts Post[]
}
model Post {
id Int #id #default(autoincrement())
title String
post String #db.VarChar(500)
created_at DateTime #default(now())
updated_at DateTime #updatedAt
user_id Int
user User #relation(fields: [user_id], references: [id])
}
//custom enums
enum UserRole {
client
admin
}
I want to create multiple schema for each models. User schema for user model, Post schema for post model. Like we use models in mongoose. Is it possible in Prisma ORM?
Since Prisma hasn't introduced any solution for this matter yet, used this awesome package Prismix and solved the issue. Thanks, everyone!
Prisma multiSchema is now supported as a preview feature.
See here https://www.prisma.io/docs/guides/database/multi-schema
It was introduced in version 4.3.0 https://github.com/prisma/prisma/issues/1122#issuecomment-1231773471
As the docs say you would add the preview feature...
generator client {
provider = "prisma-client-js"
previewFeatures = ["multiSchema"]
}
Then in your datasource you note the schemas...
datasource db {
provider = "mysql"
url = env("DATABASE_URL")
schemas = ["User", "Post"]
}
And finally in each model you add the ##schema attribute...
model User {
id Int #id #default(autoincrement())
username String #unique #db.VarChar(255)
role UserRole #default(admin)
posts Post[]
##schema("User")
}
model Post {
id Int #id #default(autoincrement())
title String
post String #db.VarChar(500)
created_at DateTime #default(now())
updated_at DateTime #updatedAt
user_id Int
user User #relation(fields: [user_id], references: [id])
##schema("Post")
}
Note:
It might not be possible to do cross schema foreign keys. I saw it mentioned somewhere, but I can't find it now.
Yes, We Can create multiple schemas for each model.
I'm new to active Android and I have done CRUD operation, but I am unable to set auto increment for the primary key. I already tried below code but it is of not use to me:
#Table(name = "Employee", id = "EmpId")
public class Employee extends Model {
#Column(name = "empid")
public long empid;
#Column(name="name")
public String name;
}
Here employee is my tablename. I have primary 2 fields, one is empid and name. I need to set auto increment value to the primary key.
How can I do that?
To do an update with a unique column as your pseudo primary key, the annotation would look something like this:
#Column(name = "empid", unique = true, onUniqueConflict = Column.ConflictAction.REPLACE)
public long empid;
As we can read in a documentation:
One important thing to note is that ActiveAndroid creates an id field
for your tables. This field is an auto-incrementing primary key.
Moreover, if you would like to create custom primary key in you model, you can check solution mentioned in GitHub issue connected with ActiveAndroid, which looks like this:
#Table(name = "Employee", id = "EmpId")
public class Employee extends Model {
#Column(name = "id")
public long id;
#Column(name="name")
public String name;
}
Then, id field is custom primary key, which will be auto-incremented.
I've got a bit of a complicated domain model I'm trying to implement and I'm having some trouble. (On top of that, I'm quite new to all this!)
I have a User domain which has multiple roles and multiple tests. The Role domain works great. The Test domain is a bit more compilciated though because it requires two foreign keys instead of just 1 like in the Role domain. The first foreign key is the user_id and the second is a uni_id (university ID).
The User domain model contains the following
class User {
static hasMany = [roles:Role, tests:Test]
Integer userId
...
static mapping = {
table 'user_data'
id generator: 'assigned', name: 'userId', type: 'long'
userId column: 'user_id'
version false
roles joinTable:[name:'user_role', key:'user_id']
tests joinTable:[name:'user_test', key:'user_id'] // Here is where I run into trouble
}
static constraints = {
}
}
The Test domain contains
class Test {
static belongsTo = User
static hasMany = [users:User]
static hasOne = [uni:Uni]
Integer testId // primary key
String testType
static mapping = {
table 'test'
id generator: 'assigned', name: 'testId', type: 'long'
testId column: 'test_id'
users joinTable:[name:'user_test', key:'test_id']
uni joinTable:[name:'user_test', key:'test_id'] // If I leave this out, everything is groovy
version false
}
static constraints = {
}
}
and the Uni domain contains
class Uni {
static belongsTo = Test
static hasMany = [tests:Test]
Integer uniId // primary key
String shortName
String fullName
static mapping = {
table 'uni'
id generator: 'assigned', name: 'uniId', type: 'long'
uniId column: 'uni_id'
version false
tests joinTable:[name:'user_test', key:'uni_id']
}
static constraints = {
}
}
If its not clear, what I'm trying to do is pull in the University ID, Test ID, and User ID to a table user_test to find based on the User ID which tests they have taken. Is there a simple way to do this?
The kinds of errors I'm getting lead me to believe that for some reason it is trying to perform all actions on the table test instead of user_test. For example,
Unsuccessful: alter table test add uni_id int not null
I'd like to be able to access the test and university information corresonding to the specific user via user.tests.testType and user.tests.uni.fullName or something to that extent. What am I doing wrong? More importantly, is there a better way to do this?! Thanks in advance!
Edit 1: something interesting I just thought of.. a user can have multiple tests, but the inverse isn’t true. A given test will never be shared among multiple people. So I think that changes things a bit.. I'll do some reading and post if I come up with anything new.
Edit 2: Here's the Role domain
class Role {
static belongsTo = User
static hasMany = [users:User]
Integer roleId
String shortName
String roleName
Integer roleLevel
static mapping = {
table 'role'
id generator: 'assigned', name: 'roleId', type: 'long'
roleId column: 'role_id'
users joinTable:[name:'user_role', column:'user_id', key:'role_id']
version false
}
static constraints = {
}
}
Edit 3: I am now trying to store all test information in the Test domain model and simply choose the Uni name to store as a field in Test, but am getting weird errors when I try this. My new files look like this
class User {
static hasMany = [roles:Role, tests:Test]
Integer userId
static mapping = {
table 'user_data'
id generator: 'assigned', name: 'userId', type: 'long'
userId column: 'user_id'
version false
roles joinTable:[name:'user_role', key:'user_id']
}
static constraints = {
}
}
and
class Test {
static belongsTo = User
Integer testId // primary key
Integer testTypeId
String testTypeName
String testUni
Date testDate
static mapping = {
table 'test'
id generator: 'assigned', name: 'testId', type: 'long'
testId column: 'test_id'
version false
}
static constraints = {
}
}
but now I'm getting the following error when I try to run it Caused by: org.hibernate.MappingException: Missing type or column for column[tests_test] on domain[User] referencing[Test]
Any idea what that's about?
Ok, one issue you have is that you're trying to share the User-to-Test association join table with the Test-to-Unit association. That's not going to work.
Lets look at it in database terms. I'm not an ASCII art expert, so I hope this diagram doesn't make your eyes bleed.
user_data (userId) |---|< (user_id) user_test (test_id) >|---| (testId) test
The diagram above shows the database implementation of the many-to-many association between the User and Test domain classes. You can see that the user_data.userId links to user_test.user_id and user_test.test_id links to test.testId.
Now here's where it starts to get weird. There are two different associations between Test and Uni: a bidirectional one-to-one and a one-to-many. I just don't understand that. But I want to illustrate an important issue with your join tables, so here it is.
test (testId) |---|< (test_id) user_test (uni_id) >|---| (uniId) uni
Because you're using the same join table (user_test) for two different associations you're asking GORM to create a table like this:
USER_TEST
- USER_ID
- TEST_ID
- UNIT_ID
GORM won't do that because join tables are supposed to have only two fields. Not only that, but also you're defining a many-to-many in database terms, and yet a bidirectional one-to-one and a one-to-many in GORM terms. Ouch!
TODO
The first change I recommend is to use a different join table for the Test-Uni association.
Finally got everything working (after a bit of modification in terms of the domain model)
class User {
static hasMany = [roles:Role, tests:Test]
Integer userId
static mapping = {
table 'user_data'
id generator: 'assigned', name: 'userId', type: 'long'
userId column: 'user_id'
version false
roles joinTable:[name:'user_role', column:'role_id', key:'user_id']
}
static constraints = {
}
}
and
class Test {
User user
Integer testId // primary key
String testType
String testUni
Date testDate
static mapping = {
table 'test'
id generator: 'assigned', name: 'testId', type: 'long'
testId column: 'test_id'
version false
}
static constraints = {
}
}
with
class Uni {
Integer uniId // primary key
String shortName
String fullName
static mapping = {
table 'uni'
id generator: 'assigned', name: 'uniId', type: 'long'
uniId column: 'uni_id'
version false
}
static constraints = {
}
}
So now what I'm doing is selecting the university from a drop down tab in my GSP and just saving it in Test as the string testUni. Then, the big change was removing all joinTables between the three and adding User user to Test. I'm still a little fuzzy on why what I was doing before didn't work, but I won't complain about a working app!
EDIT: for the tl;dr crowd, my question is: How do I access the mappings from inside the ForeignKeyConvention in order to determine the table name that a given type is mapped to?
The long version:
I am using Fluent NHibernate to configure NHibernate, and I have a custom foreign key convention that is failing when I alias tables and columns.
My tables use a convention where the primary key is always called "PK", and the foreign key is "FK" followed by the name of the foreign key table, e.g., "FKParent". For example:
CREATE TABLE OrderHeader (
PK INT IDENTITY(1,1) NOT NULL,
...
)
CREATE TABLE OrderDetail (
PK INT IDENTITY(1,1) NOT NULL,
FKOrderHeader INT NOT NULL,
...
)
To make this work, I've built a custom ForeignKeyConvention that looks like this:
public class AmberForeignKeyConvention : ForeignKeyConvention
{
protected override string GetKeyName( Member member, Type type )
{
if ( member == null )
return "FK" + type.Name; // many-to-many, one-to-many, join
return "FK" + member.Name; // many-to-one
}
}
This works so long as my entities are named the same as the table. But it breaks when they aren't. For example, if I want to map the OrderDetail table to a class called Detail, I can do so like this:
public class DetailMap : ClassMap<Detail>
{
public DetailMap()
{
Table( "OrderDetail" );
Id( o => o.PK );
References( o => o.Order, "FKOrderHeader" );
...
}
}
The mapping works for loading a single entity, but when I try to run any kind of complicated query with a join, it fails, because the AmberForeignKeyConvention class is making incorrect assumptions about how the columns are mapped. I.e., it assumes that the foreign key should be "FK" + type.Name, which in this case is Order, so it calls the foreign key "FKOrder" instead of "FKOrderHeader".
So as I said above: My question is, how do I access the mappings from inside the ForeignKeyConvention in order to determine a given type's mapped table name (and for that matter, their mapped column names, too)? The answer to this question seems to hint at the right direction, but I don't understand how the classes involved work together. When I look through the documentation, it's frightfully sparse for the classes I've looked up (such as the IdMapping class).
the idea is to load the mappings
public class AmberForeignKeyConvention : ForeignKeyConvention
{
private static IDictionary<Type, string> tablenames;
static AmberForeignKeyConvention()
{
tablenames = Assembly.GetExecutingAssembly().GetTypes()
.Where(t => typeof(IMappingProvider).IsAssignableFrom(t))
.ToDictionary(
t => t.BaseType.GetGenericArguments()[0],
t => ((IMappingProvider)Activator.CreateInstance(t)).GetClassMapping().TableName);
}
protected override string GetKeyName( Member member, Type type )
{
return "FK" + tablenames[type]; // many-to-one
}
}
Reverse engineering an existing database to map with N-Hibernate using Fluent N-Hibernate.
How can I map this?
Address table
Id
Address1
Address2
Person table
Id
First
Last
Types
Id
TypeName
PersonAddress table (A person can have home, business etc addresses)
Id
PersonId (Id from person table)
AddressId (Id from address table)
TypeId (Id from types lookup table HOME, BUSINESS etc..)
Any help would be great. Thanks
Here's another tricky one in addition to above mapping. Don't know how easy it would be to map it.
Party Table
Id
Person Id points to Person
Identifiers Tables
Id
Party Id
Type Id
Identifier value
Employee table
Employee Id No party or person table has foreign key to this table. The employee id is stored in the
identifiers table. so for e.g. The identifier table is used store values for different types. The identifiers for a given party could DriverLicense, EmployeeId, SSN, Credit Card numeber etc, this could be many values.
Sample identifier data
Id, PartyId, TypeId, IdentifierValue
1 , 1, 1, EMPLID-1234
2 , 2, 1, EMPLID-4567
3 , 3, 1, EMPLID-34354
I am trying to get my head around this and just can't get it to mapped.
// this answer assumes you have functional Address, Person, Type, and PersonAddress objects.
public class AddressMap : ClassMap<Address>
{
public AddressMap()
{
Id(x=>x.Id);
Map(x=>x.Address1);
Map(x=>x.Address2);
}
}
public class PersonMap : ClassMap<Person>
{
public PersonMap()
{
Id(x=>x.Id);
Map(x=>x.First);
Map(x=>x.Last);
}
}
public class TypeMap : ClassMap<Type>
{
public TypeMap()
{
Id(x=>x.Id);
Map(x=>x.TypeName);
}
}
public class PersonAddressMap : ClassMap<PersonAddress>
{
public PersonAddressMap()
{
Id(x=>x.Id);
References(x=>x.Person, "PersonId");
References(x=>x.Address, "AddressId");
References(x=>x.Type, "TypeId");
}
}