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Questions - constraints

How can I define a relationship so that it can only have exactly two entries in SQLAlchemy?

I have two tables DOOR and ROOM (s. below) where each door should be associated with exactly two rooms and each room can be associated with one or more doors. How can i define this constraint with SQL...
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d3nigma

sqlalchemy

constraints

Votes: 0

Answers: 1

Latest Answer

At the Python level, you could listen for events that modify the number of doors related to a room. @sa.event.listens_for(Room.doors, 'append') def door_append_handler(target, value, initiator): i...
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snakecharmerb

Constrain total number of array elements less than predetermined value

I'm trying to create an array with a constraint on the total number of array elements less than given value. For example, I want to generate a random array where the total number of elements less than...
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mdems

random

constraints

verilog

system-verilog

Votes: 0

Answers: 2

Latest Answer

Calling a user defined function in a constraint creates problems because the values for the input argument (in this case abs_vals) get picked before calling the function, and the output of the functio...
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dave_59

SQL constraint over multiple tables

I have a small group of tables that I'm connecting with SQL Server. Here's a basic diagram: Note: there are other columns in some tables which I've removed for brevity. All of this works okay, but th...
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John Ohara

sql

sql-server

constraints

Votes: 0

Answers: 1

Latest Answer

Add a PageID to RouteParam and make the FK (PageID, RouteID). Also propagate the PageID down to PageParam. PageParam would then have the two FKs: FK (PageID, PageVarianID), FK (PageID, RouteParamId). ...
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Olivier Jacot-Descombes

How to determine that a class implements a specific interface with self-referencing, generic constraints?

I have a DbContext-derived class and want to get a list of all DbSet<Entity> properties whose generic argument Entity matches the following criteria: Entity must not inherit from a class. Entit...
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Raheel Khan

c#

generics

reflection

constraints

Votes: 0

Answers: 0

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