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Django migration strategy for renaming a model and relationship fields
...different name, and the migration it creates will lose any data in the old table." Django 2.1 Docs For me, it was sufficient to create an empty migration, add the model renames to it, then run makemigrations as usual.
– hlongmore
Jan 15 '19 at 9:05
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How to Implement Custom Table View Section Headers and Footers with Storyboard
...simply drag a UIView onto the canvas, lay it out and then set it in the tableView:viewForHeaderInSection or tableView:viewForFooterInSection delegate methods.
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How to alter a column's data type in a PostgreSQL table?
...entation here: http://www.postgresql.org/docs/current/interactive/sql-altertable.html
ALTER TABLE tbl_name ALTER COLUMN col_name TYPE varchar (11);
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Oracle的列操作(增加列,修改列,删除列)，包括操作多列 - 数据库(内核) - 清...
...(增加列,修改列,删除列)，包括操作多列增加一列： alter table emp4 add test varchar2(10);修改一列： alter table emp4 modify test varchar2(20);删除一列：alter 增加一列：
alter table emp4 add test varchar2(10);
修改一列：
alter table emp4 modify test va...
Combining “LIKE” and “IN” for SQL Server [duplicate]
...y, the IN statement creates a series of OR statements... so
SELECT * FROM table WHERE column IN (1, 2, 3)
Is effectively
SELECT * FROM table WHERE column = 1 OR column = 2 OR column = 3
And sadly, that is the route you'll have to take with your LIKE statements
SELECT * FROM table
WHERE column...
List of ANSI color escape sequences
... underlined (4) and the last part clears all this (0).
As described in the table below, there are a large number of text properties you can set, such as boldness, font, underlining, &c. (Isn't it silly that StackOverflow doesn't allow you to put proper tables in answers?)
Font Effects
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How do you use variables in a simple PostgreSQL script?
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Here's an example of using a variable in plpgsql:
create table test (id int);
insert into test values (1);
insert into test values (2);
insert into test values (3);
create function test_fn() returns int as $$
declare val int := 2;
begin
return (SELECT id FROM test ...
Why is Dictionary preferred over Hashtable in C#?
In most programming languages, dictionaries are preferred over hashtables.
What are the reasons behind that?
19 Answers
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UITableView row animation duration and completion callback
Is there a way to either specify the duration for UITableView row animations, or to get a callback when the animation completes?
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How big can a MySQL database get before performance starts to degrade
...data. The most important scalability factor is RAM. If the indexes of your tables fit into memory and your queries are highly optimized, you can serve a reasonable amount of requests with a average machine.
The number of records do matter, depending of how your tables look like. It's a difference ...