I am trying to create mysql table using groovy domain class. I have one master table and other table with has reference to field in the master table.
Let me explain more clearly. I have a master table
QualificationMaster
`````````````````
QualificaitonID
QualificationName
QualificaitonDuration
UserQualificationMap
```````````````````
Username
Email
QualificationID (this field refers to QualificationID in QualificationMaster)
Please help me in getting this done by using groovy domain class with sample snippet...I searched a lot but I find it so confusing..please help me as i am very new to groovy and helps me a lot. I am using GGTS IDE for this.
Check this out:
class QualificationMaster{
String QualificationName
Integer QualificaitonDuration
}
class UserQualificationMap{
String Username
String Email
QualificationMaster Qualification
}
You do not have to use QualificationMaster.QualificaitonID as primary key for QualificationMaster. QualificationMaster.id is created by default for each domain class (you can check it in your db).
Therefore you can make a reference to QualificationMaster from UserQualificationMap. It will be mapped as QualificationMaster's primary key in UserQualificationMap table.
Moreover try to use shorter and lowercased names for properties in your domain classes. For example change QualificationMaster.QualificationName to QualificationMaster.name and QualificationMaster.QualificaitonDuration to QualificationMaster.duration.
Related
I am trying to pick up SQLalchemy and run constantly run into the following problem:
is there a way to retrieve some sort of a metadata string from session.commit(), which contains the current primary id SQLalchemy just created ?
You can simply get it from the SQLA object following its commit:
my_record= MyTable(id=None, FieldA='testing')
cs.add(myTable)
cs.commit()
print(my_record.id) # will be the primary id assuming it is autoincrement
I am trying to generate schema from the DataNucleus SchemaTool for a mysql database, that will store countries and states. Here is a sample of that code:
#PersistenceCapable
Public class State{
private String shortCode;
private String fullName;
#Column(allowsNull = "true",name="country_id")
private Country countryId;
}
The following are my schemaGeneration properties:
datanucleus.ConnectionDriverName=com.mysql.jdbc.Driver
datanucleus.ConnectionURL=jdbc:mysql://localhost:3306/geog
datanucleus.ConnectionUserName=geog
datanucleus.ConnectionPassword=geogPass
datanucleus.schema.validateTables=true
datanucleus.mapping.Catalog=geog
datanucleus.mapping.Schema=geog
In my Country class as well, I have a mapping from a Collection, so that the FK reference for States to the Country table is built correctly.
But there is one problem. In the SQL script generated, the Index part has the Schema name as part of the index name itself, which fails the entire script. Here is that piece:
CREATE INDEX `GEOG`.`MST_STATE_N49` ON `GEOG`.`MST_STATE` (`COUNTRY_ID`);
Notice the schema name in the GEOG.MST_STATE_N49 part of the index' name.
I tried setting the schema and catalog name to blank but that yields a ''.MST_STATE_N49 which still fails.
I am using MySQL Server 5.7.17 using the 5.1.42 version of the JDBC driver (yes, not the latest) on Data nucleus JDO 3.1
Any hints on how I can get rid of the schema/catalog name in the generated DDL?
Why are you putting "datanucleus.mapping.Schema" when using MySQL ? MySQL doesnt use schema last I looked. Similarly the "datanucleus.mapping.Catalog" is effectively defined by your URL! MySQL only actually supports JDBC catalog, mapping on to "database", as per this post. Since DataNucleus simply uses the JDBC driver then catalog is the only useful input.
Consequently removal of both schema and catalog properties will DEFAULT to the right place.
After the comment above from Neil Stockton, I commented out both the properties and it worked. Effectively, this is what is needed:
datanucleus.ConnectionDriverName=com.mysql.jdbc.Driver
datanucleus.ConnectionURL=jdbc:mysql://localhost:3306/geog
datanucleus.ConnectionUserName=geog
datanucleus.ConnectionPassword=geogPass
datanucleus.schema.validateTables=true
Hopefully, I can get the answer to the other question (Pt. 2 in my reply-comment above) as well.
I have two tables which are Many-To-One mapped. However, it is important to maintain the order of the second table, so when I use automapping, Fluent automapper creates a bag. I changed this to force a list by using this command:
.Override(Of ingredients)(Function(map) map.HasMany(Function(x) x.PolygonData).AsList())
(VB.NET syntax)
So I say "AsList" and instead of using a bag, the mapping xml which gets generated contains a list now. Fine so far. However,
the statement generated cannot be handled by MySQL. I use MySQL55Dialect to create the statements and I use exactly that version. But it creates the following create:
create table `ingredients` (
Id INTEGER NOT NULL AUTO_INCREMENT,
Name FLOAT,
Amout FLOAT,
Soup_id INTEGER,
Index INTEGER,
primary key (Id)
)
It crashes because of the line "Index INTEGER," but I don't know what to do here. Any ideas?
Thanks!!
Best,
Chris
I would suspect that Index could be a keyword for MySQL. To avoid such conflict, we can define different Index column name (sorry for C# notation)
HasMany(x => x.PolygonData)
.AsList(idx => idx.Column("indexColumnName").Type<int>())
I have a problem inserting a related row through Entity Framework 5. I'm using it with RIA Services and .NET Framework version 4.5. The database system is MySQL 5.6. The connector version is 6.6.5.
It raises a Foreign Key constraint exception.
I've chosen to simplify the model to expose my issue.
LDM
Provider(id, name, address)
Article(id, name, price)
LinkToProvider(provider_id, article_id, provider_price)
// Id's are auto_increment columns.
First I create a new instance of Article. I add an instance of LinkToProvider to the LinkProvider collection of the article. In this LinkToProvider object the product itself is referenced. An existing provider is also referenced.
Then I submit the changes.
Sample code from the DataViewModel
this.CurrentArticle = new Article();
...
this.CurrentArticle.LinkToProvider.Add(
new LinkToProvider { Article = this.CurrentArticle, Provider =
this.ProviderCollection.CurrentItem }
);
...
this.DomainContext.articles.Add(this.CurrentArticle);
this.DomainContext.SubmitChanges();
NOTE :
At the begining Entity Framework inserts the product well. Then it fails because it tries to insert a row in the LinkToPrivder table with an unkown product id like the following.
INSERT
INTO LinkToProvider
VALUES(5, 0, 1.2)
It puts 0 instead of the generated id.
But if I insert a product alone without any relations the product id is generated in the database correctly.
Any help will be much appreciated !
Thank you.
I found the answer.
You need to bind the result from the stored procedure to the id column in the edmx model
So I have to modify my stored procedure to add an instruction to show the last instered id for the article table on the standard output.
SELECT LAST_INSERT_ID() AS NewArticleId;
Then I added the binding with the name of the column name returned by the stored procedure. Here it's NewArticleId.
It's explained here : http://learnentityframework.com/LearnEntityFramework/tutorials/using-stored-procedures-for-insert-update-amp-delete-in-an-entity-data-model/.
I am working to use django's ContentType framework to create some generic relations for a my models; after looking at how the django developers do it at django.contrib.comments.models I thought I would imitate their approach/conventions:
from django.contrib.comments.models, line 21):
content_type = models.ForeignKey(ContentType,
verbose_name='content type',
related_name="content_type_set_for_%(class)s")
object_pk = models.TextField('object ID')
content_object = generic.GenericForeignKey(ct_field="content_type", fk_field="object_pk")
That's taken from their source and, of course, their source works for me (I have comments with object_pk's stored just fine (integers, actually); however, I get an error during syncdb on table creation that ends:
_mysql_exceptions.OperationalError: (1170, "BLOB/TEXT column 'object_pk' used in key specification without a key length")
Any ideas why they can do it and I can't ?
After looking around, I noticed that the docs actually state:
Give your model a field that can store a primary-key value from the models you'll be relating to. (For most models, this means an IntegerField or PositiveIntegerField.)
This field must be of the same type as the primary key of the models that will be involved in the generic relation. For example, if you use IntegerField, you won't be able to form a generic relation with a model that uses a CharField as a primary key.
But why can they do it and not me ?!
Thanks.
PS: I even tried creating an AbstractBaseModel with these three fields, making it abstract=True and using that (in case that had something to do with it) ... same error.
After I typed out that really long question I looked at the mysql and realized that the error was stemming from:
class Meta:
unique_together = (("content_type", "object_pk"),)
Apparently, I can't have it both ways. Which leaves me torn. I'll have to open a new question about whether it is better to leave my object_pk options open (suppose I use a textfield as a primary key?) or better to enforce the unique_togetherness...