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10 Newer Entries Showing entries 121 to 130 of 888 10 Older Entries

Displaying posts with tag: PHP (reset)

PHP for MySQL Striped View
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Back in May I explained how to create MySQL striped views with session variables. A couple folks wanted to know how to implement them through PHP programs. The trick is sharing the same connection between a call to the function before a query against the striped view.

I’ve updated the MySQL example beyond the Hobbit analogy from the prior post. It now uses the following database components:

  • A striped AUTHORIZED_USER view
  • A FUNCTION_QUERY view to …
  [Read more...]
Free Oracle PHP Book
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Six years ago, I wrote Oracle Database 10g Express Edition PHP Web Programming for the release of the express edition. It was a lot of fun to write because I enjoy the PHP programming language, but unfortunately sales didn’t measure up too well. That’s probably because the population of PHP developers working with Oracle was small.

Today it seems there are more PHP developers …

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One-way Password Crypting Flaws
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I was talking with a client and the topic of password crypting came up. From my background as a C coder, I have a few criteria to regard a mechanism to be safe. In this case we’ll just discuss things from the perspective of secure storage, and validation in an application.

  1. use a digital fingerprint algorithm, not a hash or CRC. A hash is by nature lossy (generates evenly distributed duplicates) and a CRC is intended to identify bit errors in transmitted data, not compare potentially different data.
  2. Store/use all of the fingerprint, not just part (otherwise it’s lossy again).
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Somebody wanted an example of how to handle column values using PHP to query a MySQL database. While I thought there were enough examples out there, they couldn’t find one that was code complete.

Well, here’s one that works using a static query. If you want to use a prepared statement, check this earlier post.

<title>Static Query Object Sample</title>
<style type="text/css">
  /* HTML element styles. */
  table …
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Statistical functions in MySQL
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Even in times of a growing market of specialized NoSQL databases, the relevance of traditional RDBMS doesn't decline. Especially when it comes to the calculation of aggregates based on complex data sets that can not be processed as a batch like Map&Reduce. MySQL is already bringing in a handful of aggregate functions that can be useful for a statistical analysis. The best known of this type are certainly:

Read the rest »

Lock Wait Timeout Errors or Leave Your Data on the Server
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If you use MySQL with InnoDB (most everyone) then you will likely see this error at some point. There is some confusion sometimes about what this means. Let me try and explain it.

Let's say we have a connection called A to the database. Connection A tries to update a row. But, it receives a lock wait timeout error. That does not mean that connection A did anything wrong. It means that another connection, call it B, is also updating a row that connection A wants to update. But, connection B has an open transaction that has not been committed yet. So, MySQL won't let you update that row from connection A. Make sense?

The first mistake people may make …

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Stop comparing stuff you don't understand
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I normally don't do this. When I see someone write a blog post I don't agree with, I often just dismiss it and go on. But, this particular one caught my attention. It was titled PHP vs Node.js: Yet Another Versus. The summary was:

Node.js = PHP + Apache + Memcached + Gearman - overhead

What the f**k? Are you kidding me? Clearly this person has NEVER used memcached or Gearman in a production environment that had any actual load.

Back in the day, when URLs and filesystems had a 1:1 mapping, it made perfect sense to have a web server separate …

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PHP error and MySQL Percona Server 5.5
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If you ever get an error with MySQL client library:

php: error while loading shared libraries: cannot open shared object file: No such file or directory

while using Percona MySQL Server 5.5 just go ahead and install Percona-Server-shared-compat package from Percona Repo:

yum install Percona-Server-shared-compat

Interviewing tip..
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I've been involved in a number of interviews over the last few weeks as a client has been loking for a MySQL DBA. When you are looking for position as a DBA in a large scale environement there are some very important things you have to know.

You absolutely must know a scripting language. In a smaller environment this often isn't necessary. You will live and die by this in a large environment. I asked every applicant one specific question..if you had to change a mysql server variable on a pool of 100 mysql servers how would you do this? It's easy when it's one,two or even a dozen servers. just log in, change the my.cnf and change it "on the …

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UTF-8 with MySQL and LAMP
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A recent question on a mailing list was the best practices for UTF-8 and PHP/MySQL. The following are the configurations I used in my multi-language projects.

MySQL UTF-8 Configuration

# my.cnf
default_character_set = utf8
character_set_client       = utf8
character_set_server       = utf8
default_character_set = utf8

PHP UTF-8 Configuration

default_charset = "utf-8"

Apache UTF-8 Configuration

AddDefaultCharset UTF-8
    AddCharset UTF-8   .htm

HTML file UTF-8 Configuration

 <meta charset="utf-8"> …
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10 Newer Entries Showing entries 121 to 130 of 888 10 Older Entries

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