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How do I add a foreign key to an existing SQLite table?
...child ADD CONSTRAINT fk_child_parent
FOREIGN KEY (parent_id)
REFERENCES parent(id);
SQLite doesn't support the ADD CONSTRAINT variant of the ALTER TABLE command (sqlite.org: SQL Features That SQLite Does Not Implement).
Therefore, the only way to add a foreig...
How to prevent custom views from losing state across screen orientation changes
...lass CustomView extends View {
private int stateToSave;
...
@Override
public Parcelable onSaveInstanceState() {
//begin boilerplate code that allows parent classes to save state
Parcelable superState = super.onSaveInstanceState();
SavedState ss = new SavedState(superState);
...
List of all index & index columns in SQL Server DB
...for:
SELECT
TableName = t.name,
IndexName = ind.name,
IndexId = ind.index_id,
ColumnId = ic.index_column_id,
ColumnName = col.name,
ind.*,
ic.*,
col.*
FROM
sys.indexes ind
INNER JOIN
sys.index_columns ic ON ind.object_id = ic.object_id and ind....
AngularJS $resource RESTful example
...s, and it will wait. It's probably best just to deal with your resource inside of a promise then() or the callback method.
Standard use
var Todo = $resource('/api/1/todo/:id');
//create a todo
var todo1 = new Todo();
todo1.foo = 'bar';
todo1.something = 123;
todo1.$save();
//get and update a tod...
How can I find a specific element in a List?
...
Use a lambda expression
MyClass result = list.Find(x => x.GetId() == "xy");
Note: C# has a built-in syntax for properties. Instead of writing getter and setter methods (as you might be used to from Java), write
private string _id;
public string Id
{
get
{
return _i...
What is the difference between pluck and collect in Rails?
...particular field. See this.
When you do:
User.first.gifts.collect(&:id)
You have objects with all fields loaded and you simply get the id thanks to the method based on Enumerable.
So:
if you only need the id with Rails 4, use ids: User.first.gifts.ids
if you only need some fields with Ra...
mysql update column with value from another table
... UPDATE participants_registrations INNER JOIN participants ON participants.id = participants_registrations.participantId INNER JOIN registrations ON registrations.id = participants_registrations.registrationId LEFT JOIN groups ON (groups.id = registrations.groupId) SET registrations.groupId = g...
Hibernate, @SequenceGenerator and allocationSize
...y 50 (default allocationSize value) - and then uses this value as entity ID.
6 Answers
...
What is the id( ) function used for?
I read the Python 2 docs and noticed the id() function:
13 Answers
13
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Hibernate throws org.hibernate.AnnotationException: No identifier specified for entity: com..domain.
...
You are missing a field annotated with @Id. Each @Entity needs an @Id - this is the primary key in the database.
If you don't want your entity to be persisted in a separate table, but rather be a part of other entities, you can use @Embeddable instead of @Entity....