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How does “do something OR DIE()” work in PHP?
I'm writing a php app to access a MySQL database, and on a tutorial, it says something of the form
4 Answers
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Getting the minimum of two values in SQL
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For MySQL or PostgreSQL 9.3+, a better way is to use the LEAST and GREATEST functions.
SELECT GREATEST(A.date0, B.date0) AS date0,
LEAST(A.date1, B.date1, B.date2) AS date1
FROM A, B
WHERE B.x = A.x
With:
GREATEST(v...
Possible to perform cross-database queries with PostgreSQL?
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If you're coming from a MySQL environment, what MySQL calls databases are really schemas (CREATE SCHEMA == CREATE DATABASE in MySQL), so if you porting something from MySQL using multiple databases, use schemas
– MkV
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C/C++中的段错误（Segmentation fault） - C/C++ - 清泛网 - 专注C/C++及内核技术
...麻烦”？
3。编程中通常碰到段错误的地方有哪些？
4。如何发现程序中的段错误并处理掉？
正文
1。什么是段错误？
下面是来自Answers.com的定义：
A segmentation fault (often shortened to segfault) is a particular error conditio...
Overriding id on create in ActiveRecord
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Perhaps what I experienced only expressed itself with mysql driver.
– jkndrkn
Feb 18 '13 at 19:30
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SQL select only rows with max value on a column [duplicate]
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I know that MySQL allows you to add non aggregate fields to a "grouped by" query, but I find that kinda pointless. Try running this select id, max(rev), rev from YourTable group by id and you see what I mean. Take your time and try to un...
How to test an SQL Update statement before running it?
...What about Transactions? They have the ROLLBACK-Feature.
@see https://dev.mysql.com/doc/refman/5.0/en/commit.html
For example:
START TRANSACTION;
SELECT * FROM nicetable WHERE somthing=1;
UPDATE nicetable SET nicefield='VALUE' WHERE somthing=1;
SELECT * FROM nicetable WHERE somthing=1; #check
CO...
How do I select an entire row which has the largest ID in the table?
...show profiles and it appears our solutions have the same performance using MySQL. For my own knowledge, do you know what DBMS has poorer performance for subselects?
– unutbu
Feb 7 '14 at 20:08
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How to use JNDI DataSource provided by Tomcat in Spring?
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auth="Container"
type="javax.sql.DataSource"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/TestDB"
username="pankaj"
password="pankaj123"
maxActive="100"
maxIdle="20"
minIdle="5"
maxWait="10000"/>
back to context.xml de spring add this
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How to add 'ON DELETE CASCADE' in ALTER TABLE statement
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Answer for MYSQL USERS:
ALTER TABLE ChildTableName
DROP FOREIGN KEY `fk_table`;
ALTER TABLE ChildTableName
ADD CONSTRAINT `fk_t1_t2_tt`
FOREIGN KEY (`parentTable`)
REFERENCES parentTable (`columnName`)
ON DELETE CASCADE
ON UP...