大约有 38,000 项符合查询结果（耗时：0.0235秒） [XML]
Reset auto increment counter in postgres
I would like to force the auto increment field of a table to some value, I tried with this:
12 Answers
...
How to version control a record in a database
...
Let's say you have a FOO table that admins and users can update. Most of the time you can write queries against the FOO table. Happy days.
Then, I would create a FOO_HISTORY table. This has all the columns of the FOO table. The primary key is th...
Can we pass parameters to a view in SQL?
...t a stored function, like:
CREATE FUNCTION v_emp (@pintEno INT)
RETURNS TABLE
AS
RETURN
SELECT * FROM emp WHERE emp_id=@pintEno;
This allows you to use it as a normal view, with:
SELECT * FROM v_emp(10)
share
...
CSS Div stretch 100% page height
...
It's simple using a table:
<html>
<head>
<title>100% Height test</title>
</head>
<body>
<table style="float: left; height: 100%; width: 200px; border: 1px solid red">
<tbody>
...
When should I use cross apply over inner join?
...readable and probably less efficient.
Update:
Just checked.
master is a table of about 20,000,000 records with a PRIMARY KEY on id.
This query:
WITH q AS
(
SELECT *, ROW_NUMBER() OVER (ORDER BY id) AS rn
FROM master
),
t AS
(
SELEC...
Nullable Foreign Key bad practice?
Let's say you have a table Orders with a foreign key to a Customer Id. Now, suppose you want to add an Order without a Customer Id, (whether that should be possible is another question) you would have to make the foreign key NULL... Is that bad practice or would you rather work with a link table bet...
In MySQL what does “Overhead” mean, what is bad about it, and how to fix it?
...uld only worry if this gets really high.
You can compare 'Optimizing the table' with the defragmenting of your hard drive.
I quote:
Every database will, over time,
require some form of maintenance to
keep it at an optimal performance
level. Purging deleted rows,
resequencing, compre...
Postgresql - change the size of a varchar column to lower length
I have a question about the ALTER TABLE command on a really large table (almost 30 millions rows).
One of its columns is a varchar(255) and I would like to resize it to a varchar(40) .
Basically, I would like to change my column by running the following command:
...
Foreign key constraints: When to use ON UPDATE and ON DELETE
...eign key constraints are quite advanced.
We'll take an example, a company table with a user table containing people from theses company
CREATE TABLE COMPANY (
company_id INT NOT NULL,
company_name VARCHAR(50),
PRIMARY KEY (company_id)
) ENGINE=INNODB;
CREATE TABLE USER (
user_...
List columns with indexes in PostgreSQL
...
Create some test data...
create table test (a int, b int, c int, constraint pk_test primary key(a, b));
create table test2 (a int, b int, c int, constraint uk_test2 unique (b, c));
create table test3 (a int, b int, c int, constraint uk_test3b unique (b), co...