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Relational Database Design Patterns? [closed]
...elationships using a foreign key.
Many-to-Many relationships with a bridge table.
Optional one-to-one relationships managed with NULLs in the FK column.
Star-Schema: Dimension and Fact, OLAP design.
Fully normalized OLTP design.
Multiple indexed search columns in a dimension.
"Lookup table" that con...
With MySQL, how can I generate a column containing the record index in a table?
...itialization without requiring a separate SET command.
Test case:
CREATE TABLE league_girl (position int, username varchar(10), score int);
INSERT INTO league_girl VALUES (1, 'a', 10);
INSERT INTO league_girl VALUES (2, 'b', 25);
INSERT INTO league_girl VALUES (3, 'c', 75);
INSERT INTO league_girl...
Auto increment primary key in SQL Server Management Studio 2012
How do I auto increment the primary key in a SQL Server database table, I've had a look through the forum but can't see how.
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Multiple columns index when using the declarative ORM extension of sqlalchemy
...just Column objects, index=True flag works normally:
class A(Base):
__tablename__ = 'table_A'
id = Column(Integer, primary_key=True)
a = Column(String(32), index=True)
b = Column(String(32), index=True)
if you'd like a composite index, again Table is present here as usual you just...
Optimise PostgreSQL for fast testing
...s should always be followed; see the version policy.
Don'ts
Do NOT put a tablespace on a RAMdisk or other non-durable storage.
If you lose a tablespace the whole database may be damaged and hard to use without significant work. There's very little advantage to this compared to just using UNLOGGED...
Postgres: INSERT if does not exist already
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There is one caveat/side effect. In a table with sequence column (serial or bigserial), even if no row is inserted the sequence is incremented at every insert attempt.
– Grzegorz Luczywo
Jul 2 '17 at 12:10
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How do I explicitly specify a Model's table-name mapping in Rails?
I have a Model class called Countries and I want it to map to a DB table called 'cc'.
2 Answers
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What is the difference between the Data Mapper, Table Data Gateway (Gateway), Data Access Object (DA
...
Your example terms; DataMapper, DAO, DataTableGateway and Repository, all have a similar purpose (when I use one, I expect to get back a Customer object), but different intent/meaning and resulting implementation.
A Repository "acts like a collection, except with m...
SQLAlchemy: cascade delete
...relationship doesn't dictate the parent-child setup. Using ForeignKey on a table is what sets it up as the child. It doesn't matter if the relationship is on the parent or child.
– d512
Aug 4 '16 at 2:04
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Generate table relationship diagram from existing schema (SQL Server) [closed]
Is there a way to produce a diagram showing existing tables and their relationships given a connection to a database?
9 Ans...