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Postgres dump of only parts of tables for a dev snapshot
... TO '/tmp/myfile.tsv'
COPY mytable FROM 'myfile.tsv'
https://www.postgresql.org/docs/current/static/sql-copy.html
You should consider maintaining a set of development data rather than just pulling a subset of your production. In the case that you're writing unit tests, you could use the same da...
SqlException from Entity Framework - New transaction is not allowed because there are other threads
...e exception you were seeing.
EDIT I revisited this question after running SQL Profiler and updated a few things to improve performance. For anyone who is interested, here is some sample SQL that shows what is created by the DB.
The first loop doesn't need to skip anything, so is simpler.
SELECT ...
How to serialize SqlAlchemy result to JSON?
...
A flat implementation
You could use something like this:
from sqlalchemy.ext.declarative import DeclarativeMeta
class AlchemyEncoder(json.JSONEncoder):
def default(self, obj):
if isinstance(obj.__class__, DeclarativeMeta):
# an SQLAlchemy class
fiel...
When to use Common Table Expression (CTE)
...bout Common table expression that is a new feature which was introduced in SQL server 2005 and available in later versions as well.
Common table Expression :- Common table expression can be defined as a temporary result set or in other words its a substitute of views in SQL Server. Common table ex...
Can a foreign key be NULL and/or duplicate?
...lls leave lots of room for errors in the query by folks who don't know how SQL (mis)handles 3VL . If a salesperson is truly not necessary for a certain r-table, just you don't include that record. A separate table can be "ProposalAssignedTo" or some such, with appropriate constraints. A query writer...
Using OR in SQLAlchemy
...ed through the docs and I cant seem to find out how to do an OR query in SQLAlchemy. I just want to do this query.
4 Answ...
delete_all vs destroy_all?
...
delete_all is a single SQL DELETE statement and nothing more. destroy_all calls destroy() on all matching results of :conditions (if you have one) which could be at least NUM_OF_RESULTS SQL statements.
If you have to do something drastic such as...
Exact difference between CharSequence and String in java [duplicate]
...escaping. This would make writing embedded code strings such as HTML, XML, SQL, or JSON much more convenient.
To quote JEP 378:
A text block is a multi-line string literal that avoids the need for most escape sequences, automatically formats the string in a predictable way, and gives the develo...
Finding all cycles in a directed graph
...To find a valid route, it depends on your data structure. For me it was a sql table full of valid route possibilities so I had to build a query to get the valid destinations given a source.
Problem 2)
Push each node as you find them into a collection as you get them, this means that you can see if...
How to expand/collapse a diff sections in Vimdiff?
...
set vimdiff to ignore case
Having started vim diff with
gvim -d main.sql backup.sql &
I find that annoyingly one file has MySQL keywords in lowercase the other uppercase showing differences on practically every other line
:set diffopt+=icase
this updates the screen dynamically & y...