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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...
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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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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What is the difference between the Data Mapper, Table Data Gateway (Gateway), Data Access Object (DA
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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...
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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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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Fastest way to flatten / un-flatten nested JSON objects
...object:
var flatten = (function (isArray, wrapped) {
return function (table) {
return reduce("", {}, table);
};
function reduce(path, accumulator, table) {
if (isArray(table)) {
var length = table.length;
if (length) {
var index ...
Counting the number of elements with the values of x in a vector
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You can just use table():
> a <- table(numbers)
> a
numbers
4 5 23 34 43 54 56 65 67 324 435 453 456 567 657
2 1 2 2 1 1 2 1 2 1 3 1 1 1 1
Then you can subset it:
> a[names(a)==435]
4...
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...