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Database Structure for Tree Data Structure
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Have a look at Managing Hierarchical Data in MySQL. It discusses two approaches for storing and managing hierarchical (tree-like) data in a relational database.
The first approach is the adjacency list model, which is what you essentially describe: having a foreign key...
Why does the order in which libraries are linked sometimes cause errors in GCC?
...llowing scenario:
myprog.o - containing main() function, dependent on libmysqlclient
libmysqlclient - static, for the sake of the example (you'd prefer the shared library, of course, as the libmysqlclient is huge); in /usr/local/lib; and dependent on stuff from libz
libz (dynamic)
How do we link...
java.lang.NoClassDefFoundError: org/hamcrest/SelfDescribing
...JECT_NAME].iml
Replaced:
<library>
<CLASSES>
<root url="jar://$APPLICATION_HOME_DIR$/lib/junit-4.11.jar!/" />
</CLASSES>
<JAVADOC />
<SOURCES />
</library>
By:
<library name="JUnit4">
<CLASSES>
<root ...
Using OpenSSL what does “unable to write 'random state'” mean?
...appening seems to be that the .rnd file in your home directory is owned by root rather than your account. The quick fix:
sudo rm ~/.rnd
For more information, here's the entry from the OpenSSL FAQ:
Sometimes the openssl command line utility does not abort with a "PRNG not seeded" error messag...
Can you configure log4net in code instead of using a config file?
...e;
roller.ActivateOptions();
hierarchy.Root.AddAppender(roller);
MemoryAppender memory = new MemoryAppender();
memory.ActivateOptions();
hierarchy.Root.AddAppender(memory);
hierarchy.Root.Level = Level.Info;
...
Where to find extensions installed folder for Google Chrome on Mac?
...lication\ Support/Google/Chrome/Default/Extensions
When installed at the root level, it's at:
/Library/Application\ Support/Google/Chrome/Default/Extensions
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Update all values of a column to lowercase
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See http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_lower
UPDATE table_name SET tag = LOWER(tag)
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Mechanisms for tracking DB schema changes [closed]
...se.
Make a backup of the current database (because stuff will go wrong) [mysqldump].
Create bookkeeping table (called _meta) if it doesn't exist.
Read current VERSION from _meta table. Assume 0 if not found.
For all .sql files numbered higher than VERSION, execute them in order
If one of t...
IntelliJ does not show 'Class' when we right click and select 'New'
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The directory or one of the parent directories must be marked as Source Root (In this case, it appears in blue).
If this is not the case, right click your root source directory -> Mark As -> Source Root.
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How do I create a new Swift project without using Storyboards?
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All it takes for not using Storyboards for the rootViewController:
1· Change AppDelegate.swift to:
import UIKit
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, di...