self-reference

Recursive reference to a list within itself [duplicate]

由 丶灬走出姿态 提交于 2019-12-10 01:52:52
问题 This question already has answers here : Why does list(my_list) modify the object? (2 answers) Closed 5 years ago . So I came across something very weird in python. I tried adding a reference to the list to itself. The code might help demonstrate what I am saying better than I can express. I am using IDLE editor(interactive mode). >>>l=[1,2,3] >>>l.append(l) >>>print(l) [1,2,3,[...]] >>>del l[:-1] >>>print(l) [[...]] So far the output is as expected. But when I do this. y=l[:] print(y) To me

Recursive function: Call php function itself

由 岁酱吖の 提交于 2019-12-10 01:00:43
问题 I just want to make sure I do it right and this will not create any conficts. I have a function which calls itself and need your approval if it's OK or not to do so? <?php function determine($the_array){ foreach ($the_array as $key => $value) { switch ($key) { case 'in': echo $value; break; case 'out': echo $value; break; case 'level': echo '<ul>'; determine($value); echo '</ul>'; break; } } } This is the array: $the_array = array( 'in' => '<li>Simple IN</li>', 'out' => '<li>Simple OUT</li>',

Many-to-many self-referential relationship in sqlalchemy

由 微笑、不失礼 提交于 2019-12-09 14:47:31
问题 I'm trying to make a self-referential many-to-many relationship (it means that Line can have many parent lines and many child lines) in sqlalchemy like this: Base = declarative_base() class Association(Base): __tablename__ = 'association' prev_id = Column(Integer, ForeignKey('line.id'), primary_key=True) next_id = Column(Integer, ForeignKey('line.id'), primary_key=True) class Line(Base): __tablename__ = 'line' id = Column(Integer, primary_key = True) text = Column(Text) condition = Column

Entity Framework self-referencing entity query results are flat AND hiearchical

由 喜夏-厌秋 提交于 2019-12-08 11:19:16
问题 I have a self-referencing entity: When I query this entity.. var query = this._context.DispositionPossibilities .Where(x => x.AreaID == areaID) .Where(x => x.IsActive == true); .. the resulting collection has EVERY item returned from the query at the root, and then the those items with ParentIDs are 'duplicated' inside the child collections (because of Navigation Properties). I can remove them by doing this: // have to ToArray() first because the child entities will be excluded if I don't..

Transaction with loopback linked server - locking issues

由 久未见 提交于 2019-12-08 09:52:22
问题 I have two databases A and B . They are both stored on one database instance. I created a loopback linked server on the instance. Database A contains one table dbo.Users and one stored procedure updating dbo.Users table. In database B I have a query which does two things: Execute the stored procedure from database A which updates the dbo.Users table. Select data from dbo.Users through the linked server. BEGIN TRANSACTION EXEC [LinkedServer].A.dbo.UpdateUser select * from [LinkedServer].A.dbo

Self-referencing a partial key of a table

由 ☆樱花仙子☆ 提交于 2019-12-08 06:44:28
I am designing a datatable (-s) for storing the list of shareholders. In case a shareholder is a nominee, it discloses the list of share owners. These all need to have a pile of similar references. Thus, I would like to store all in one table. Nominees are registered shareholders and thus, they have an account number in the system, from which I get the data. Opposed to this, share owners that are coming from nominee disclosure have no their own account number, and share account number of the nominee. I add a uniquifier to the table. I would like to assume that all registered shareholders and

Core Data: Self referencing table

由 限于喜欢 提交于 2019-12-08 01:02:16
问题 I have an Entity in my Core Data model that contains a reference to itself. i.e. A Page can have a child collection of pages. When compiling i get the warning: "Page.pages -- to-many relationship does not have an inverse: this is an advanced setting (no object can be in multiple destinations for a specific relationship)" Now I have read that core data requires an inverse relationship to maintain integrity and would like to provide this. I don't mind my data model being changed it is an early

Hibernate3: Self-Referencing Objects

由 情到浓时终转凉″ 提交于 2019-12-06 05:57:55
问题 Need some help on understanding how to do this; I'm going to be running recursive 'find' on a file system and I want to keep the information in a single DB table - with a self-referencing hierarchial structure: This is my DB Table structure I want to populate. DirObject Table: id int NOT NULL, name varchar(255) NOT NULL, parentid int NOT NULL); Here is the proposed Java Class I want to map (Fields only shown): public DirObject { int id; String name; DirObject parent; ... For the 'root'

How to get the current script's code in Python?

由 徘徊边缘 提交于 2019-12-06 05:12:18
问题 I want to get the current script as a string in a variable in Python. I found two sub-optimal ways, but I hope there is a better solution. I found: The inspect import has a getsource method, but that only returns the code of one function (or class or whatever), but not the entire script. I can't find a way to pass the object of the entire script to getsource . I could find the file location of the script file using __file__ or sys.argv[0] and open it to read. But this seems too indirect to me

SQL self-referencing query. JOIN

由 笑着哭i 提交于 2019-12-06 03:49:29
i need to query a self referencing relationship for unit prerequisites. i know that you need to use two Joins, do i SELECT my column and then join it to itself ? SELECT u.unit_code, u.name + ' is a prerequisite of ' + u.name AS unit_prerequisite FROM units AS u so far that is what i have, not sure where my joins have to be made? not even sure if that first part is correct. You do this by joining the table to itself on the self-referencing column: SELECT u.unit_code, u1.name + ' is a prerequisite of ' + u2.name AS unit_prerequisite FROM units AS u1 inner join units u2 on u2.RefId = u1.RefId You
订阅 self-reference