Can someone help me with my situation. I have the following code.
class Employee {
Integer empId
String firstName
String lastName
static constraints = {
empId()
firstName()
lastName()
}
static mapping = {
id generator:'assigned', name:'empId'
version false
}
}
The code allows me to save employee through 'create' but gives the following error message
"Employee not found with id null" and also in the list, all the employees are listed but clicking on any Emp Id gives the same error. Please help. This is driving me nuts.
Rocky
Thanks for your reply. Like I mentioned I am able to save the empId in the database but get that message nonetheless and see the list with assigned ids (empId). The link points to employee/show with no number at end. However employee/show/22(empId) works fine. employee/edit/22 works too but update does not work.
I am not using any assigned sequence. Just some random integer. Maybe a better example would be to use SSN instead of empId.
Thank you once again.
You are a great help buddy. Appreciate your time and patience. I am not writing any special update or save (I am too new to dig too deep). Just using grails to generate-all. However, I did find a workaround. I changed the domain class to add variable id (Long) and added empId setter method to allocate the empId value to id. That did it. Here is my code.
class Employee {
Long id
Long empId
String firstName
String lastName
static constraints = {
empId()
firstName()
lastName()
}
static mapping = {
id generator:'assigned', name:'empId', column: 'emp_id'
version false
}
public void setEmpId(Long empId){
this.empId = empId
this.id = empId
}
}
Please feel free to suggest if you have a better way of doing that.
Regards
Rocky
If you are using the "assigned" sequence, then you have to assign the objects ids yourself before saving them. Otherwise your objects will be saved with a null or 'default 0' id. If you want GORM to assign an id for you, you need to use another type of generator, like "sequence" generator. It would be like:
id name: 'customId', generator: 'sequence', params: [sequence:'some_sequence']
More info on id generators here.
Related
I am currently trying to unwind a list of objects that I want to merge to the database using the Neo4J Client. What I would like to do is unwind the list and create the nodes with a label generated based on a property from the items themselves instead of hardcoding a label name. From what I can find I have to use the APOC merge method to do so. However, I am unable to translate this to the Neo4J client. In the neo4J explanation they yield a node after the apoc.merge.node call and then return the node. However, I cannot simply return the node nor can I set the node (I got to the point of just messing about, and at one point I got the labels to work but it overwrote all properties with the last item in the list).
I seem to miss something fundamental but i'm not quite sure what. Does anyone here know how to do this with neo4J client (and if possible, give a bit of an explanation what is going on)? I am very new to the development world and I feel I am just missing a crucial piece of understanding when it comes to this..
The code that I tried that turned all properties into the last node's properties but at least created the labels as I expected:
public async void CreateBatchItems(List<TToDataBase> itemList)
{
await Client.Cypher
.Unwind(itemList, "row")
.Merge("(n)")
.With("row, n")
.Call("apoc.merge.node([n.Name], n)").Yield("node")
.Set("n += node")
.ExecuteWithoutResultsAsync();
}
Thank you in advance!
Edit:
Some clarification about the input:
The objects are actually very basic, as (at least for now), they merely contain a name and an objectID (and these object ID's are later used to create relations). So its a very basic class with two properties:
public class Neo4JBaseClass
{
public Neo4JBaseClass() { }
public Neo4JBaseClass(string name, string objectId)
{
Name = name;
ObjectId = objectId;
}
[JsonProperty(PropertyName = "ObjectId")]
public string ObjectId { get; set; }
[JsonProperty(PropertyName = "Name")]
public string Name { get; set; }
}
I have also tried a slight variation where this class also has the added property
[JsonProperty(PropertyName = "PropertyMap")]
public IProperty PropertyMap { get; set; }
where PropertyMap is another basic object holding the name and objectId. This seemed like a good idea for future proofing anyway, so the propertylist can be easily expanded without having to change the base object.
[EDITED]
The main issue is that Merge("(n)") matches any arbitrary node that already exists.
You have not shown the data structure for each element of itemList, so this answer will assume it looks like this:
{Name: 'SomeLabel', id: 123, Props: {foo: 'xyz', bar: true}}
With above data structure, this should work:
public async void CreateBatchItems(List<TToDataBase> itemList)
{
await Client.Cypher
.Unwind(itemList, "row")
.Call("apoc.merge.node([row.ObjectId], row.id)").Yield("node")
.Set("node += row.Props")
.ExecuteWithoutResultsAsync();
}
[UPDATE]
The data structure you added to your question is very different than what I had imagined. Since neither of the properties in a row is a map, .Set("node += row.Props") would generate an error.
Using your data structure for each row, this might work:
public async void CreateBatchItems(List<TToDataBase> itemList)
{
await Client.Cypher
.Unwind(itemList, "row")
.Merge("(n:Foo {id: row.ObjectId})")
.Set("n += row.Name")
.ExecuteWithoutResultsAsync();
}
This code assigns the node label Foo to all the generated nodes. A node should always have a label, which improves clarity and also tends to improve efficiency -- especially if you also create indexes. For example, an index on :Foo(id) would make the above query more efficient.
This code also assumes that the id property is supposed to contain a unique Foo node identifier.
I am working with Grails 3.2.8. I would like to allow both options when generating an id. Is there a way to use assigned and falling back to sequence if unassigned? I tried getting the next id within a constructor and setting id there but running into issues. Any help/guidance would be most appreciated.
class Foo {
static mapping = {
id generator:'assigned'
}
}
vs
class Foo {
static mapping = {
id generator:'sequence'
}
}
Ive tried using mapping set to assigned and setting the id within the domain constructor of beforeValidate function. Neither are working for me. Examples below.
class Foo{
Foo(){
def id = Foo.find("from Foo order by id desc")
id = id ? id : 0
this.id = id
}
static mapping = {
id generator:'assigned'
}
}
class Foo{
def beforeValidate() {
def id = Foo.find("from Foo order by id desc")
id = id ? id : 0
this.id = id
}
static mapping = {
id generator:'assigned'
}
}
Thanks in advance for your help.
Is there a way to use assigned and falling back to sequence if
unassigned?
No, not directly anyway. You could use assigned and when you wanted to fall back on the sequence you could send a query to the database to retrieve the next sequence value and then assign it yourself. I think that is probably as close as you can probably get.
First of all, you need to understand HQL; in your examples you are returning Foo not id, so it's clearly wrong.
Second, you shouldn't depend on the table for next value of id, because it's not guaranteed to be correct -- you might face id is not unique kinda errors.
Third, you aren't incrementing the id, this way you will end up getting the same, most likely 0, every time.
Here is what you can do, use database sequence -- depends on the database.
"select id_seq.nextval from dual" // for Oracle
Finally, it's a very bad idea -- unless you are having a very good reason for it.
So I have a grails model looking like this:
class Tree {
Long id;
String name;
static hasMany = [branches: Branch
}
class Branch {
Long id;
String name;
static belongsTo = [tree: Tree]
}
The issue is that in DB, the Tree id is a number, while the tree_id in the Branch table is a varchar.
The db model is a de facto foreign key that is not enforced at all as a constraint.
Gorm generate a query that is not handled by my database: it tries to bing a numerical value where text is expected:
ERROR util.JDBCExceptionReporter - ORA-01722: invalid number
How can I tell GORM to convert the value before binding the parameter ?
I looked in the join table config but I did not find anything relevant.
Have you tried using sqlType in column definition in mappings?
class Branch {
Long id
String name
static belongsTo = [tree: Tree]
static mapping = {
tree column: 'TREE_ID', sqlType: "char"
}
}
Unable to test right now, but do let me know.
I'm trying to add an object to a database-first ORM EntitySet in an MVC project. I use a piece of code something like this:
public static Boolean CreateListing(string title, string description)
{
ListingEntities ce = new ListingEntities();
ce.Ads.AddObject(new Ad()
{
ID = Guid.NewGuid(),
Title = title,
Description = description,
});
return ce.SaveChanges() == 1;
}
However, the SaveChanges method throws a Data.UpdateException which is thrown by a SqlClient.SqlException. The latter says
"Cannot insert the value NULL into column 'ID', table 'Listings.dbo.Ads'; column does not allow nulls. INSERT fails.
The statement has been terminated."
I wholeheartedly agree. I just don't see why the ID should be null when it seems I set it immediately prior. Any suggestions?
Thanks,
Nathan
Someone else on my team configured the database to create its own ID's, and the issue is resolved.
I tried to change the standard 'id' in grails:
calls Book {
String id
String title
static mapping {
id generator:'assigned'
}
}
unfortunately, I soon noticed that this breaks my bootstrap. Instead of
new Book (id:'some ISBN', title:'great book').save(flush:true, failOnError:true)
I had to use
def b = new Book(title:'great book')
b.id = 'some ISBN'
b.save(flush:true, failOnError:true)
otherwise I get an 'ids for this class must be manually assigned before calling save()' error.
but that's ok so far.
I then encountered the same problem in the save action of my bookController. But this time, the workaround didn't do the trick.
Any suggestions?
I known, I can rename the id, but then I will have to change all scaffolded views...
That's a feature of databinding. You don't want submitted data to be able to change managed fields like id and version, so the Map constructor that you're using binds all available properties except those two (it also ignores any value for class, metaClass, and a few others).
So there's a bit of a mismatch here since the value isn't managed by Hibernate/GORM but by you. As you saw the workaround is that you need to create the object in two steps instead of just one.
I can't replicate this problem (used Grails 2.0.RC1). I think it might be as simple as a missing equal sign on your static mapping = { (you just have static mapping {)
Here's the code for a domain object:
class Book {
String id
String name
static mapping = {
id generator:'assigned'
}
}
And inside BootStrap.groovy:
def init = { servletContext ->
new Book(name:"test",id:"123abc").save(failOnError:true)
}
And it works fine for me. I see the id as 123abc.
You need to set the bindable constraint to true for your id prop, e.g.
class Employee {
Long id
String name
static constraints = {
id bindable: true
}
}