The association names sqlmetal generates have been the source of much frustration. Sometimes the association is simply the column name with "Id" taken off the end, sometimes it generates an association name based on the foreign key constraint name.
I simply cannot figure out what steps it uses to generate these names, and a recent schema change has drastically altered the association names once again, so I'd like to get a handle on this.
I have two tables which reference each other in a sort of chain. Something like this:
class In
{
int Id;
EntityRef<Out> Yields; // YieldsId => FK_Out_Source
EntitySet<Out> In_Source; // FK_In_Source
}
class Out
{
int Id;
EntityRef<In> Yields; // YieldsId => FK_In_Source
EntitySet<In> Out_Source; // FK_Out_Source
}
These were the classes prior to the schema change, where there was an extra FK field between In and Out tables. After deleting that field, sqlmetal now generates this:
class In
{
int Id;
EntityRef<Out> Yields; // YieldsId => FK_Out_Source
EntitySet<Out> Out; // FK_In_Source
}
class Out
{
int Id;
EntityRef<In> In; // YieldsId => FK_In_Source
EntitySet<In> Out_Source; // FK_Out_Source
}
The previous classes were perfectly symmetrical as they should be, but now the generated classes are completely asymmetrical. Can anyone explain this?
Since there seems to be no rhyme or reason to this, I created a command line tool that wraps sqlmetal and rewrites the association names. It's included in my open source Sasa utilities framework, and is called sasametal.
Related
Is there a way to disable the 'remove-the-plural-s' feature in Postgraphile?
I have a table OS in my database and am using the very awesome Postgraphile library to create a GraphQL interface for free. Everything is great, but Postgraphile is truncating my table name, thinking it is plural. So I get allOs instead of allOses and createO, updateO, etc...
I tried:
Adding an underscore after the table name, and then it just retains the entire thing with an underscore.
Adding an underscore (O_S) and then the plural has capital-s allOS but the singular is O_
A smart comment specifying E'#name os' but it still drops the s
A smart comment specifying E'#name oss' which then pluralizes correctly allOsses (haha) and keeps both for the singular oss
PS in case you see this Benjie/other contributors, your documentation is incredible and the library will save me months of work.
This change is performed by PostGraphile's inflector; however it doesn't always get it right (e.g. in this case) but fortunately it's possible to override it with a small plugin.
In this case, it's probably best to add specific exceptions to the pluralize and singularize functions; you can do this using makeAddInflectorsPlugin from our inflection system. Be sure to pass true as the second argument so that the system knows you're deliberately overwriting the inflectors.
const { makeAddInflectorsPlugin } = require('graphile-utils');
module.exports = makeAddInflectorsPlugin(oldInflectors => ({
pluralize(str) {
if (str.match(/^os$/i)) {
return str + 'ses';
}
return oldInflectors.pluralize(str);
},
singularize(str) {
if (str.match(/^osses$/i) {
return str.substr(0, 2);
}
return oldInflectors.singularize(str);
}
}), true);
I'm glad you're enjoying PostGraphile 🤘
function updateFirebase(){
const fb=firebase.database().ref()
//get field values
author = document.getElementById('uname').value
user_email = document.getElementById('umail').value
data = {author, user_email}
//update database
fb.child('Article/').update(data);
}
</script>
I have problem with my code. I want to update the data inside a table named "Article". Article has generated items with a unique key/id and each key has its own content. Lets say I want to be able to edit the "author" or change the "title", the problem is they each have a randomly generated key/id that I cant access. for example that "-LS39kReBHrKGqNj7h_". I can only save the data inside the "Article" tree but I cant change the "author" or the "title". How do i get a workaround this so I can change those properties?
Here is how my firebase looks like
It depends whether you have the record reference on the frontend before update or not (whether you have fetched it before you are trying to update it).
But generally, you have two options
You can store the key reference as an "id" field on the object.
To achieve that, you need two step process when creating the record at the first place
// Creates a new record in DB and returns it to you. Now you can get the "key"
const newRecord = firebase.database().ref('TABLE_NAME_REF').push();
newRecord.set({
id: newRecord.key
...
});
This is great if you fetch the list of records on the frontend and then you want to update one of them. Then you can just build the ref path like this
fb.child('Article/' + record.id ).update(data); // where record is the prefetched thing
You need to find the element based on its fields first. And once you have it, you can update it right away.
To achieve this, you can simply do something like:
firebase.database()
.ref('TABLE_NAME_REF') // let's say 'Article'
.orderByChild('RECORD_KEY') // Let's say 'author'
.equalTo('KEY_VALUE') // let's say 'zoranm'
.limitToFirst(1)
.once("value")
.then(res => {
// You need to loop, it always returns an array
res.forEach(record => {
console.log(record.key); // Here you get access to the "key"
fb.child('Article/' + record.key ).update(data); // This is your code pasted here
})
})
How can I access filteredArray in my .ts component? Because right now it is accessible only inside ng-container.
<ng-container *ngIf="(userList | filter: 'name' : value) as filteredArray">
<tr *ngFor="let user of filteredArray">
<td>{{user.name}}</td>
<td>{{user.group}}</td>
</tr>
<div>Count: {{ filteredArray.length }}</div>
</ng-container>
How can I modify the code in order to obtain what I want? Thank you for your time!
To answer your question directly: it's not possible the way you describe it. But read on.
Pipes (sometimes still called "filters") should be used only to format data, i.e. prepare it in a human-readable form. For example, the build-in date pipe can be used to transform an ISO string to a string such as "March 21st, 1995", which is how a human from the USA might expect to read the date.
The way you're using pipes is not recommended, precisely because of the question you have. You've essentially put application logic inside a template, which is an anti-pattern and beats the purpose of having easy-to-read declarative templates, which Angular uses in order to figure out how to update DOM.
You should move the filtering logic back to the class. For example, instead of setting this.userList = xxx, you could have a function which you call every time, such as this.changeUserList(xxx).
changeUserList (list) {
this.userList = list
this.filteredArray = list.filter(...)
}
You can put this logic in a setter as well, which allows you to run custom code when you write the usual this.userList = list, but you'll need a separate (usually prefixed private) property on the class where you'd actually store the value. It's not really a limitation since you can also have a trivial getter, so you can still us this.userList normally as a getter without having to remember to use this._userList, essentially tucking this away as the get/set pair's implementation detail.
private _userList
public set userList (list) {
this._userList = list
this.filteredArray = list.filter(...)
}
public get userList (list) { return this._userList }
Observables could really come in handy here as well, since you could just rx.map the userList$ to filteredArray$ with an Array#filter.
public userList$
public filteredArray$ = this.userList$.pipe(map(arr => arr.filter(...))
Then in the template, you can use the async pipe.
*ngIf="filteredArray$ | async as filteredArray"
Avoid doing the following.... but it works for demo purposes 😃
Create a component (e.g. demo-element.component.ts) that takes a single #Input() value:any
Add this new component as the first child of the <ng-container>, and give it a template reference #containerRef e.g.:
<ng-container *ngIf="(userList | filter: 'name' : value) as filteredArray">
<demo-element #containerRef [value]="filteredArray"></demo-element>
In your main component, add
#ViewChild('containerRef') ref;
ngAfterViewInit() {
this.filteredArray = this.ref.value; // Terrible pattern, but answers the question:-)
}
I hope this below code will help you.
<div class="rsrvtn_blk" *ngIf="(items | fSearch:firstname) as filteredItems">
<div class="col-md-3 pl-0" *ngFor="let item of filteredItems">
// you can display the filtered content here
</div>
</div>
I'm designing a Spring Boot REST API that will be backed by MySQL. It has occurred to me that I want, effectively, two separate models for all my domain objects:
Model 1: Used between the outside world (REST clients) and my Spring REST controllers; and
Model 2: The entities used internally between by Spring Boot app and the MySQL database
For instance I might have a contacts table for holding personal/contact info:
CREATE TABLE contacts (
contact_id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
contact_ref_id VARCHAR(36) NOT NULL,
contact_first_name VARCHAR(100) NOT NULL,
...many more fields
);
and the respective Spring/JPA/Hibernate entity for it might look like:
// Groovy pseudo-code!
#Entity
class Contact {
#Id
#Column(name = "contact_id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
Long id
#Column(name = "contact_ref_id")
UUID refId
#Column(name = "contact_first_name")
String firstName
// ...etc.
}
If I only had a single model paradigm, then when Jackson goes to serialize a Contact instance (perhaps fetched back from the DB) into JSON and send it back to the client, they'd see JSON that looks like:
{
"id" : 45,
"refId" : "067e6162-3b6f-4ae2-a171-2470b63dff00",
"firstName" : "smeeb",
...
}
Nothing like exposing primary keys to the outside world! Instead, I'd like the serialized JSON to omit the id field (as well as others). Another example might be a lookup/reference table like Colors:
# Perhaps has 7 different color records for ROYGBIV
CREATE TABLE colors (
color_id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
color_name VARCHAR(20) NOT NULL,
color_label VARCHAR(20) NOT NULL,
color_hexcode VARCHAR(20) NOT NULL,
# other stuff here
);
If the corresponding Color entity looked like this:
#Entity
class Color {
#Id
#Column(name = "color_id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
Long id
#Column(name = "color_name")
String name
#Column(name = "color_label")
String label
#Column(name = "color_hexcode")
String hexcode
// ...etc.
}
Then with only one model it would serialize into JSON like so:
{
"id" : 958,
"name" : "Red",
"label" : "RED",
"hexcode" : "ff0000"
}
But maybe I just want it to come back as a simple string value:
{
"color" : "RED"
}
So it seems to me that I either need two separate models (and mapper classes that map between them) or I need a way to annotate my entities or configure either Spring, Jackson or maybe even Hibernate to apply certain transformations on my entities at the right time. Do these frameworks offer anything that can help me here, or am I going to have to go with two distinct domain models here?
You can actually accomplish this with just one model and I think it is the easiest way if you are just looking for hiding fields, custom formatting, simple transformation of attributes etc. Having two models require transformation from one model to another and vice-versa which is a pain. Jackson provides a lot of useful annotations which can be used to customize the output. Some of the annotations that can be useful for you are listed below
#JsonIgnore - ignore a field/attribute. You can hide your id field using this annotation.
#JsonInclude - Can be used to specify when a field should be present in output. For eg: Whether a field should be present in output if it is null
#JsonSerialize - You can specify a custom serializer for an attribute. For eg: You have an attribute 'password' and you want to output password as '****'.
#JsonFormat - You can apply a custom format to a field. This is very useful if you have date/time fields
#JsonProperty - If you want to give a different name for your field in your output. For eg: You have a field 'name' in your model and you want to display it as 'userName' in the output.
I have a document like this:
{
Name : val
AnArray : [
{
Time : SomeTime
},
{
Time : AnotherTime
}
...arbitrary more elements
}
I need to update "Time" to a Date type (right now it is string)
I would like to do something psudo like:
foreach record in document.AnArray { record.Time = new Date(record.Time) }
I've read the documentation on $ and "dot" notation as well as a several similar questions here, I tried this code:
db.collection.update({_id:doc._id},{$set : {AnArray.$.Time : new Date(AnArray.$.Time)}});
And hoping that $ would iterate the indexes of the "AnArray" property as I don't know for each record the length of it. But am getting the error:
SyntaxError: missing : after property id (shell):1
How can I perform an update on each member of the arrays nested values with a dynamic value?
There's no direct way to do that, because MongoDB doesn't support an update-expression that references the document. Moreover, the $ operator only applies to the first match, so you'd have to perform this as long as there are still fields where AnArray.Time is of $type string.
You can, however, perform that update client side, in your favorite language or in the mongo console using JavaScript:
db.collection.find({}).forEach(function (doc) {
for(var i in doc.AnArray)
{
doc.AnArray[i].Time = new Date(doc.AnArray[i].Time);
}
db.outcollection.save(doc);
})
Note that this will store the migrated data in a different collection. You can also update the collection in-place by replacing outcollection with collection.