Mounting NFS Share on Windows 10 & 11 with Write Access

It is easy to mount a drive from Linux NFS share on Windows 10 & 11 machines. To do that make sure you have NFS Client (Services for NFS) is installed from Programs and Features. Following is the command to mount the NFS drive. Note that this command will run on cmd (Command Prompt) and not on PowerShell.

mount \<IP_ADDRESS>\<PATH_TO_DIR>\ drive:

For example, if the IP address of the NFS share is 10.235.0.10 and the directory you want to share is /var/www and you want to mount it to your Z drive, then you can run the following command.

mount \\10.235.0.10\var\www z:

But when you mount the drive you can browse the files using your Windows Explorer but you cannot create new files nor edit any files. To get write access on NFS share you have to make a small change in Windows registry before mounting the drive. Follow these steps.

  1. Open regedit by typing it in the search box end pressing Enter.
  2. Browse to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ClientForNFS\CurrentVersion\Default.
  3. Create a new New DWORD (32-bit) Value inside the Default folder named AnonymousUid and assign the UID found on the Linux directory as shared by the NFS system. This is the UID of the user that has the write access to that directory on Linux system.
  4. Create a new New DWORD (32-bit) Value inside the Default folder named AnonymousGid and assign the GID found on the Linux directory as shared by the NFS system. This is the GID of the group that has the write access on the directory on Linux system.Windows 10: Regedit NFS AnonymousUid and AnonymousGid
  5. Restart the NFS client or reboot the machine to apply the changes.

Now run the mount command and you will get the write access.

Why we moved from OpenShift to Google Cloud

The good old days

When OpenShift was in its version 1 it was great from customer’s point of view with low budget. OpenShift v1 had free offers to deploy app and add a custom domain to it. There was no SSL support but it could be handled via CloudFlare solution, making overall solution a great one.

Then there comes OpenShift v2

RedHat then launched OpenShift v2 and added a restriction that gears will be shutdown after certain period of inactivity and also removed the support for custom domain.

That was the time that we had to move to some other cloud platform that could support our apps with low resources and without investing anything.

Since all good things in life are free.

Google Cloud to the rescue

So we came across Google Cloud platform offering and we had $300 credit in free trial for next 6 months. That was more than enough for us to start with. And in fact they have micro virtual machine instances that are free for life with 30gb storage. That is more than enough for small apps to run for free that are under experiments or don’t have any monetization plans.

So, we migrated several of our apps from OpenShift to Google Cloud and started leveraging free credits provided by Google.

Just this week we consumed all our credit and our trial expired. Our virtual machine instances were shutdown, but it didn’t take long that we enabled billing on our project and downgraded our instances to micro ones which is free. That gave us such a relief that our apps are still running although with low resources but it is fine as that are not our revenue generating apps and are just experiments.

Setup Laravel with Docker containers

Docker

Docker has captured my attention lately and has been growing exponentially for last few years. Docker has revolutionized the virtualization space and has given DevOps engineers and developers a new set of tools that can ease their development as well as infrastructure resource utilization. Mostly Node.js apps have been deployed with Docker but it is not limited to only that. If you’ve been developing apps for web using PHP and Laravel framework then you are lucky that community has developed some great tools to utilize docker in their development workflow. If you are new to Docker and want to learn more about Docker then visit their website docker.com specially the section What is Docker?

Laradock

Laradock does the hard part and facilitate developers to quickly and easily setup Laravel development environment in seconds. Follow the these steps to get started.

Setup fresh environment then install Laravel inside docker

  • Create project directory. e.g. myproject
  • Create another directory within myproject directory for source that you will use commit to git repo. eg. app
  • Clone the laradock repo inside myproject folder, this will create laradock folder
git clone https://github.com/laradock/laradock.git
  • Edit the docker-compose.yml file to map to your project directory once you have it (eg. – ../app:/var/www)
  • Run the following command
docker-compose up -d nginx mysql redis beanstalkd
  • Enter the workspace
docker-compose exec workspace bash
  • cd to /var
  • Install Laravel
composer create-project laravel/laravel www
  • Open your .env file and set the following
DB_HOST=mysql
REDIS_HOST=redis
QUEUE_HOST=beanstalkd

Now open your browser and visit http://localhost

You will see running Laravel app. That was cool!

You can also connect to mysql using these settings.

Host: localhost
User: root
Password: root

If you want to add more services see the official laradock docs. It support tons of other services like memcache, pgsql etc.

Daily Use

Following are some docker related commands that you want to use on daily basis once your development environment is setup.

  • To bring up the servers to run application
docker-compose up -d nginx mysql
  • Enter workspace container to run commands like artisan, composer, phpunit, gulp etc.
docker-compose exec workspace bash

or on Windows PowerShell

docker exec -it {containerid} bash
  • List current running containers
docker ps
  • List current project containers
docker-compose ps
  • Close all running containers
docker-compose stop
  • Delete all existing containers
docker-compose down
  • View the log files
docker logs {container-name}

 

 

List of FREE services Startups should be using

I have curated a list of free tools, services, and apps that startups could and in fact should use to grow at the initial stage. Free doesn’t mean they lack quality, instead these free tools are from top-notch companies like RedHat, Google, Asana, GitHub and in all areas from infrastructure to version controlling to marketing and sales to project management.

Have a look at this list here and don’t forget to give your feedback.

I compiled this list a long time ago and recently updated it but it still might have some outdated links that I didn’t get chance to update yet. Feel free to let me know and I’ll update it.

Enjoy!

How can I test if mod_rewrite on my server is enabled and working?

Note that mod_rewrite can only be used with web server Apache. Follow the instructions below to check whether module mod_rewrite is installed and correctly configured on your server.

Create the file .htaccess and add these two lines

RewriteEngine on
RewriteRule ^testing.php$ modrewrite.php

This tells the web server to load modrewrite.php when testing.php is requested.

Create the file modrewrite.php with this line

<?php echo "mod_rewrite works"; ?>

Create the file testing.php with this line

<?php echo "mod_rewrite does not work"; ?>

Now use your web browser to load testing.php. If you see “mod_rewrite works” your server has a working mod_rewrite instance. If you see anything else, including an internal server error, your server is not properly configured for mod rewrite.

What J talked about in 2013

The WordPress.com stats helper monkeys prepared a 2013 annual report for this blog.

Here’s an excerpt:

The concert hall at the Sydney Opera House holds 2,700 people. This blog was viewed about 37,000 times in 2013. If it were a concert at Sydney Opera House, it would take about 14 sold-out performances for that many people to see it.

Click here to see the complete report.

 

How to install new ROM on Android phone

Following are the instructions to install new ROM on your Android phone using ClockworkMod recovery touch method.

-Download Appropriate Rom
-Place on root of your sdcard
-Reboot Recovery
-Select “wipe data/factory reset”
-Select “mounts and storage” category
-Select “format /boot”
-Select “format /system”
-Return to main page
-Select “advanced” Category
-Select “wipe dalvik cache”
-Select “wipe battery stats”
-Return to main page
-Select “install zip from sdcard”
-Select “choose zip from sdcard”
-Select “CronMod-3.x.x-x-rc_signed.zip”
-Answer when promted
-Reboot
-Enjoy 

[Ref: http://forum.xda-developers.com/showthread.php?t=1946517]

2012 in review

The WordPress.com stats helper monkeys prepared a 2012 annual report for this blog.

Here’s an excerpt:

4,329 films were submitted to the 2012 Cannes Film Festival. This blog had 24,000 views in 2012. If each view were a film, this blog would power 6 Film Festivals

Click here to see the complete report.

 

Converting Oracle DATE types and PHP/Unix Timestamps

If you need to convert between Oracle date and PHP/Unix timestamp then you might need to implement two function in Oracle.

The following two Oracle functions implement this for DATE types.

To convert a UNIX timestamp into an Oracle DATE type:

CREATE OR REPLACE
    FUNCTION unixts_to_date(unixts IN PLS_INTEGER) RETURN DATE IS
        /**
         * Converts a UNIX timestamp into an Oracle DATE 
         */
        unix_epoch DATE := TO_DATE('19700101000000','YYYYMMDDHH24MISS');
        max_ts PLS_INTEGER := 2145916799; -- 2938-12-31 23:59:59
        min_ts PLS_INTEGER := -2114380800; -- 1903-01-01 00:00:00
        oracle_date DATE;

        BEGIN

            IF unixts > max_ts THEN
                RAISE_APPLICATION_ERROR(
                    -20901,
                    'UNIX timestamp too large for 32 bit limit'
                );
            ELSIF unixts < min_ts THEN
                RAISE_APPLICATION_ERROR(
                    -20901,
                    'UNIX timestamp too small for 32 bit limit' );
            ELSE
                oracle_date := unix_epoch + NUMTODSINTERVAL(unixts, 'SECOND');
            END IF;

            RETURN (oracle_date);

    END;

The following PHP script shows how this might be used. Note that this script requires PHP 5.x+, as it uses the new OCI extension function names:

<?php
$conn = oci_connect('scott', 'tiger');

$sql = "
    SELECT
        *
    FROM EMP
    WHERE
        hiredate
    BETWEEN
        unixts_to_date(:startdate)
    AND
        unixts_to_date(:enddate)
    ORDER BY
        hiredate
    DESC
    ";

$stmt = oci_parse($conn, $sql);

// Bind a UNIX timestamps to :startdate and :enddate
oci_bind_by_name($stmt, ":startdate", mktime(0,0,0,1,1,1981));
oci_bind_by_name($stmt, ":enddate", mktime(0,0,0,1,1,1990));

oci_execute($stmt);

print "NAME  : HIREDATE\n";
while ( $row = oci_fetch_assoc($stmt) ) {
   print "{$row['ENAME']} : {$row['HIREDATE']}\n";
}
oci_free_statement($stmt);

oci_close($conn);
?>

In reverse, the following function returns a UNIX timestamp given an Oracle DATE type:

CREATE OR REPLACE
    FUNCTION date_to_unixts(oracle_date IN DATE) RETURN PLS_INTEGER IS
        /**
         * Converts an Oracle DATE to a UNIX timestamp
         */
        unix_epoch DATE := TO_DATE('19700101000000','YYYYMMDDHH24MISS');
        max_date DATE := TO_DATE('20380101000000','YYYYMMDDHH24MISS');
        min_date DATE := TO_DATE('19030101000000','YYYYMMDDHH24MISS');
        unix_ts PLS_INTEGER;

        BEGIN

            IF oracle_date > max_date THEN
                RAISE_APPLICATION_ERROR( -20902,'Date too large for 32bit UNIX timestamp' );
            ELSIF oracle_date < min_date THEN
                RAISE_APPLICATION_ERROR( -20902,'Date too small for 32bit UNIX timestamp' );
            ELSE
                unix_ts := (oracle_date - unix_epoch) / (1/86400);
            END IF;

            RETURN (unix_ts);

        END;

The following query shows how it might be used:SELECT
    ename,
    TO_CHAR(hiredate, 'YYYY') AS hired_year,
    TO_CHAR(hiredate, 'YYYYMM') AS hired_month,
    TO_CHAR(hiredate, 'ddth Mon, YYYY') AS hired_pretty
    date_to_unixts(hiredate) AS hired_unixts
FROM
    emp
ORDER BY
    hiredate

It’s now easy to convert the timestamp into a formatted date, using thedate() function as you loop through the result set.

 

Working with Dates and Times in Oracle and PHP

Both PHP and Oracle provide functionality manipulating dates and times. Which to use and when?

If you’re new to PHP or Oracle, working out how to handle dates efficiently can be tricky. You may have strategies, which you’ve applied successfully on other platforms, but will they fit to the combination of Oracle and PHP?

This Oracle+PHP recipe should help you understand the functionality, available in both PHP and Oracle, for working with dates and times and how they relate to each other. In doing so, it should help you decide where to draw line in deciding which technology will handle what, and answer questions like “Do I calculate the difference between these two dates in PHP or Oracle?”

Dates and Times in Oracle

Oracle provides three data types for storing date/time values:

  • The DATE type, which represents a date and time. A value stored in a DATE field contains “components” corresponding to the century, year, month, day, hour, minute and second. Dates can be anywhere in the range from January 1, 4712 B.C., to December 31, 9999 A.D.
  • The TIMESTAMP type, available since Oracle9i, is effectively an extended form of the DATE type and complies with ANSI SQL. It provides greater precision in time, supporting fractions of a second up to nine places and is also capable of storing time zone information.
  • The INTERVAL type, since Oracle9i, which supports storage of a time difference such as “two years and five months” or “three days, 18 hours and 45 minutes” and can be summed with a DATE or TIMESTAMP to produce a new DATE / TIMESTAMP value.

The focus here will be on the DATE type, although much that applies to DATE also applies to TIMESTAMP. (For more background about TIMESTAMP and INTERVAL types, read Jonathan Gennick’s Oracle Magazine articles ” Datetime Datatypes Add Precision” and ” Finding the Time in Between” (both published in the Nov.-Dec. 2002 issue).

How Oracle Stores DATEs. The first thing to grasp about the DATE type in Oracle is that its internal representation allows it to be displayed and manipulated in many different ways. It is effectively independent of any specific string format. If you SELECT a DATE type, Oracle automatically converts it to readable string, but this is not how the value is actually been stored.

Selecting the current system time using SYSDATE, which returns a value of type DATE and is the current date and time set for the operating system on which the database resides :

SELECT SYSDATE FROM dual /* e.g. 25-JUL-05 */

The format is controlled by the Oracle parameterNLS_DATE_FORMAT, and can changed on a session basis (see below). To get a feeling for the internal representation:

SELECT DUMP(SYSDATE) FROM dual /* e.g. Typ=13 Len=8: 213,7,7,25,23,7,15,0 */

Comma-separated values in the result correspond to the bytes Oracle uses to store each component of a date and time, from century down to second One important note here; when comparing DATE types, all the DATE’s components will be compared, down to the seconds. In some cases you may want to compare two dates on a different basis, such as the year, month or day. In such cases functions like TRUNC can be useful to round down the hours, minutes and seconds components of the two DATEs you are comparing. See ” Date Arithmetic” below for more detail.

If you’re familiar with OOP, it may also be helpful to think of DATE types as objects. They possess both properties (year, month, hour etc.) and behavior, such as

SELECT SYSDATE - 7 FROM dual /* e.g. 18-JUL-05 */

This returns the date seven days ago. Further “behavior” includesDATE comparisons, which implies you canSORT BY,GROUP BY, find datesBETWEEN and so on, and subtraction: subtract oneDATE from another to get the integer difference in days (or anINTERVAL type, when usingTIMESTAMP values).

Converting Between DATE Types and Strings. The TO_DATE() and TO_CHAR() functions are used to convert between Oracle DATE”objects” and human readable date strings. Both functions take three arguments; the value to convert, an optional format mask and an optional string identify a language (e.g. FRENCH). Conceptually the format mask is similar to a regular expression; you specify a pattern for a date, which tells Oracle how to relate a matching string to a DATE type. The format mask is described in the Oracle Database SQL Reference under ” Format Models.”

Working with TO_CHAR. Here’s a simple example, again using the SYSDATE function:

SELECT TO_CHAR( SYSDATE, 'YYYY-MM-DD HH24:MI:SS' ) FROM dual
    /* e.g. 2005-07-26 17:34:04 */

Looking at format mask in detail, the’YYYY’ denotes a four-digit year,’MM’ a two digit month,’DD’ a two-digit day of the month,’HH24′ the hours in a 24-hour clock,’MI’ the minutes between 0 and 59, and’SS’ the seconds between 0 and 59. Note the following characters are passed from the format mask into the output “as-is”:

/ - , . ; :

Further strings can be “passed through” by enclosing them in quotes:

SELECT TO_CHAR(SYSDATE, '"The time is now " HH24:MI:SS "precisely"') FROM dual
    /* e.g. The time is now 17:38:22 precisely

There are many more format mask patterns available to address a wide range of use cases, as you will find the documentation.

Note: TO_CHAR can also be used with TIMESTAMP types.

Working with TO_DATE. Oracle can parse strings into DATE types, using the same format masks as TO_CHAR. Given a string like 20050726173102:

SELECT TO_DATE( '20050726173102', 'YYYYMMDDHH24MISS' ) FROM dual

Or to convert “Jul 26, 2005 17:13:05”, I can use:

SELECT TO_DATE('Jul 26, 2005 17:13:05', 'Mon DD, YYYY HH24:MI:SS') FROM dual

Note: ForTIMESTAMP types the equivalent function isTO_TIMESTAMP.

Changing the default date format. Oracle displays DATE types, by default, according to the format mask defined in the NLS_DATE_FORMAT parameter. This can be changed in the session like:

ALTER SESSION SET NLS_DATE_FORMAT = 'YYYY-MM-DD HH24:MI:SS'

Date arithmetic. To determine the date six days after the 26th July, 2005, I simply add the value 6 to theDATE object:

SELECT TO_DATE( '20050726173102', 'YYYYMMDDHH24MISS' ) + 6 FROM dual
    /* e.g. 2005-08-01 17:13:05 */

The smallest whole unit for this type of operation is a single day. To subtract 18 hours, I need the appropriate fraction of a day:

SELECT TO_DATE( '20050726173102', 'YYYYMMDDHH24MISS' ) - (1/24 * 18) FROM dual
    /* e.g. 2005-07-25 23:31:02 */

Similarly, to add 59 seconds:

SELECT TO_DATE( '20050726173102', 'YYYYMMDDHH24MISS' ) + (1/(24*60*60) * 59) FROM dual

To work in months or years, given that neither can be expressed in a constant number of days (bearing in mind given leap years and months with different numbers of days), you need theADD_MONTHS function. To add twelve months to a date:

SELECT ADD_MONTHS( TO_DATE( '20050726173102', 'YYYYMMDDHH24MISS' ), 12) FROM dual
    /* e.g. 2006-07-26 17:31:02 */

Note: To subtract months, use a negative sign.

The LAST_DAY function returns the last day of the month for a DATE type:

SELECT LAST_DAY( TO_DATE( '20050701', 'YYYYMMDD' ) ) FROM dual
    /* e.g. 2005-07-31 00:00:00 */

TheTRUNC function rounds down theDATE, according to the date mask it is provided as the second argument. You might use it when makingDATE comparisons where you want to eliminate units such as seconds and minutes from the comparison:

SELECT TRUNC( TO_DATE( '20050726173102', 'YYYYMMDDHH24MISS' ), 'DD' ) FROM dual
    /* e.g. 2005-07-26 00:00:00 */

If no date mask is provided,TRUNC will round down theDATE to the start of the day it represents.

Other date-related functions include MONTHS_BETWEEN, for the integer difference in months between two DATE types, NEXT_DAY, to obtain a DATE type of the next week day matching a string literal (for example, ‘MONDAY’), and ROUND, similar to TRUNC, but returning the nearest DATE rounded up or down.

Building SQL Statements using Dates

Some simple examples of using the DATE type in an SQL statement, using the “emp” (employees) table (part of the sample data that comes with an Oracle installation). The “hiredate” column of the “emp” table stores values using the DATE type.

Locating all employees hired between two dates:

SELECT
    ename, TO_CHAR(hiredate, 'ddth Mon, YYYY')
FROM
    emp
WHERE
    hiredate
BETWEEN
    TO_DATE('1980-01-01','YYYY-MM-DD')
AND
    TO_DATE('1985-01-01','YYYY-MM-DD')
ORDER BY
    hiredate
DESC

Adding a new employee:

INSERT INTO emp
   (
        empno,
        ename,
        job,
        mgr,
        hiredate,
        sal,
        deptno
    )
VALUES
   (
        8002,
        'JOHNSON',
        'ANALYST',
        7566,
        TO_DATE('2005-07-22','YYYY-MM-DD'),
        3000,
        20
    )

Finding all employees who have been with the company for more than 15 years, using anINTERVAL type returned form theTO_YMINTERVAL function:

SELECT
    *
FROM
    emp
WHERE
    SYSDATE - TO_YMINTERVAL('15-00') >  hiredate

Dates and Times in PHP

A list of all available functions, based around the UNIX timestamp, can be found in the PHP Manual in the Date and Time Functions section. The focus here will be the date() and mktime() functions, which will typically be the functions you use most. Note that PHP version 5.1.x introduces additional date related functionality, while the examples here restrict themselves to operations available in earlier PHP versions 4.3.x and 5.0.x, although they are also forwards compatible with PHP 5.1.x.

The raw material of dates and times in PHP is the UNIX timestamp; the number of seconds before or after the UNIX epoch, which occurred at 00:00:00 UTC (GMT) on the January 1, 1970. To see a UNIX timestamp, simply print the result of PHP’s time() function; which is equivalent to Oracle’s SYSDATE:

<?php
print time(); // e.g. 1122391862
?>

To add or subtract units of days, hours, minutes, you convert the unit to seconds and apply it directly to the timestamp. Performing arithmetic using units of month and year requires the mktime() function (see below).

Formatting UNIX timestamps. The date() function is used to format UNIX timestamps:

<?php
print date('Y-m-d H:i:s',time()); // e.g. 2005-07-26 17:31:02
?>

The masks for the date() function are well documented in the manual. Any characters thatdate() does not recognize are automatically “passed though” into the output, such as punctuation characters. Characters, which could be mistaken for part of the format, can be escaped with a backslash, for example:

<?php
print date('l \t\he jS of F',1122391862); // e.g. Tuesday the 26th of July
?>

Resulting in “Tuesday the 26th of July.”

Note: If you place the format mask inside double quotes you may need a double backslash to escape certain characters; see the PHP Manual on string types and double quotes for details.

The date() function can also be useful for certain calculations:

<?php
$years = range(2005, 2020);
foreach ( $years as $year ) {
    if ( date('L', mktime(0,0,0,1,1,$year) ) ) {
        print "$year is a leap year\n";
    }
}
?>

Which tells me:
    2008 is a leap year
    2012 is a leap year
    2016 is a leap year
    2020 is a leap year

Note also the gmdate() function, which is almost exactly the same as thedate() function except that it converts the result to Greenwich Mean Time (UTC).

Creating and manipulating UNIX timestamps. The mktime() function is used to generate a UNIX timestamp from a date, given integers values which represent the components of the date. You could regard mktime() as the parallel to Oracle’s TO_DATE function. For example:

<?php
$year = 2005;
$month = 7;
$day = 27;
$hour = 12;
$minute = 34;
$second = 43;

print mktime($hour, $minute, $second, $month, $day, $year);
?>

Themktime() function takes care of adjustments required when boundaries, such as that between months are crossed:

<?php
$year = 2005;
$month = 7;
$day = 27 + 10; // Add 10 days
$hour = 12;
$minute = 34;
$second = 43;

print date('Y-M-d H:i:s',mktime($hour, $minute, $second, $month, $day, $year));
    // e.g. 2005-Aug-06 12:34:43
?>

Here, attempting to givemktime()”July 37″ results in the correct adjustment into August.

To find the last day of a given month, you can use the proceeding month along with a zero value as the day of that month. For example:

<?php
$year = 2005;
$month = 8; // August
$day = 0; // Last day of July
$hour = 12;
$minute = 34;
$second = 43;

print date('Y-M-d',mktime($hour, $minute, $second, $month, $day, $year));
?>

As with the date() function, there’s also a gmmktime() function which also adjusts to GMT.

Problems with dates and time in PHP. One limitation of UNIX timestamps is they are tied to the 32-bit limit of today’s mainstream CPU’s and operating systems. It means you can only represent a range of dates up to the year 2038 and back to 1902 on UNIX platforms. If this limitation poses a problem for your application, you may find the PEAR Date library a useful, albeit slower, alternative.

Another problem area is localization; the date() function only supports English weekday and month names. You may find the easiest practical solution, if you only need to support a handful of languages, is to translate the names using associative arrays.

Note that work is in progress to enhance PHP’s native date and time functions. You’ll find this outlined by Derick Rethans, one of the core PHP developers, in his PHP Time Handling talk which he gave at ApacheCON 2005 in Germany.

Drawing the Line

So the question is where do you draw the line? Where do you place the responsibility for handling date related operations? In PHP or Oracle? This section discusses the options, to help you make informed decisions.

In general, Oracle’s date facilities are more powerful than PHP’s, allowing greater flexibility when it comes to parsing date strings or formatting date output, thanks to a wider range of date formatting masks. Add to that the 32-bit limitation of the UNIX timestamp, that TIMESTAMP can store time zones and localization issues and you may consider passing off all date related work to Oracle. It should be pointed out though that many Web applications, particularly intranet applications, only target a single locale region, so operating within a single language and time zone. Also the range of a UNIX timestamp is often more than enough of the type of data the application will be handling. In such cases, PHP’s date time functions should pose no problems.

Date storage. Considering date and time storage, with some databases it may be necessary to use UNIX timestamps such as PHP5’s built-in SQLite. With Oracle it’s better to use DATE or TIMESTAMP as your column types, for storage for data and time values. The supporting functionality makes date operations easy, particularly when SELECTing based on DATEs and TIMESTAMPs. You’ll also find visually checking dates becomes much easier, as tools like SQL*Plus automatically display dates in a human readable form.

Date formatting. One argument against Oracle’s date formatting capabilities, when thinking in terms of a layered architecture, is that formatting output in your application’s data storage layer is “bad practice”, this being the job of the presentation layer.

If you’re in the (unusual) position of writing an application to run against multiple database implementations, this may be a valid argument. In such cases you may well want to investigate what John Lim has provided ADOdb to help with this problem—see his “Tips on Writing Portable SQL”, “Data Types” section.

More commonly, you’ll be developing against a single database, so vendor abstractions won’t be an issue. You might want to consider having Oracle format a date for you in a variety of ways, rather than trying to massage dates in PHP, as the following query suggests:

SELECT
    ename,
    TO_CHAR(hiredate, 'YYYY') AS hired_year,
    TO_CHAR(hiredate, 'YYYYMM') AS hired_month,
    TO_CHAR(hiredate, 'DD Mon, YYYY') AS hired_pretty,
    TO_CHAR(hiredate, 'DD Mon, YYYY', 'NLS_DATE_LANGUAGE=GERMAN') AS hired_german
FROM
    emp
ORDER BY
    hiredate

Alternatively (or in addition), returning a UNIX timestamp as part of the result fits nicely with PHP’s date() function (see below). Some of Oracle’s format masks, such as “Month”, pads the output with space characters so using date() in such instances may mean fewer lines of code.

Converting Oracle DATE types and Unix Timestamps. The following two Oracle functions implement this for DATE types.

To convert a UNIX timestamp into an Oracle DATE type:

CREATE OR REPLACE
    FUNCTION unixts_to_date(unixts IN PLS_INTEGER) RETURN DATE IS
        /**
         * Converts a UNIX timestamp into an Oracle DATE 
         */
        unix_epoch DATE := TO_DATE('19700101000000','YYYYMMDDHH24MISS');
        max_ts PLS_INTEGER := 2145916799; -- 2938-12-31 23:59:59
        min_ts PLS_INTEGER := -2114380800; -- 1903-01-01 00:00:00
        oracle_date DATE;

        BEGIN

            IF unixts > max_ts THEN
                RAISE_APPLICATION_ERROR(
                    -20901,
                    'UNIX timestamp too large for 32 bit limit'
                );
            ELSIF unixts < min_ts THEN
                RAISE_APPLICATION_ERROR(
                    -20901,
                    'UNIX timestamp too small for 32 bit limit' );
            ELSE
                oracle_date := unix_epoch + NUMTODSINTERVAL(unixts, 'SECOND');
            END IF;

            RETURN (oracle_date);

    END;

The following PHP script shows how this might be used. Note that this script requires PHP 5.x+, as it uses the new OCI extension function names:

<?php
$conn = oci_connect('scott', 'tiger');

$sql = "
    SELECT
        *
    FROM EMP
    WHERE
        hiredate
    BETWEEN
        unixts_to_date(:startdate)
    AND
        unixts_to_date(:enddate)
    ORDER BY
        hiredate
    DESC
    ";

$stmt = oci_parse($conn, $sql);

// Bind a UNIX timestamps to :startdate and :enddate
oci_bind_by_name($stmt, ":startdate", mktime(0,0,0,1,1,1981));
oci_bind_by_name($stmt, ":enddate", mktime(0,0,0,1,1,1990));

oci_execute($stmt);

print "NAME  : HIREDATE\n";
while ( $row = oci_fetch_assoc($stmt) ) {
   print "{$row['ENAME']} : {$row['HIREDATE']}\n";
}
oci_free_statement($stmt);

oci_close($conn);
?>

In reverse, the following function returns a UNIX timestamp given an OracleDATE type:

CREATE OR REPLACE
    FUNCTION date_to_unixts(oracle_date IN DATE) RETURN PLS_INTEGER IS
        /**
         * Converts an Oracle DATE to a UNIX timestamp
         */
        unix_epoch DATE := TO_DATE('19700101000000','YYYYMMDDHH24MISS');
        max_date DATE := TO_DATE('20380101000000','YYYYMMDDHH24MISS');
        min_date DATE := TO_DATE('19030101000000','YYYYMMDDHH24MISS');
        unix_ts PLS_INTEGER;

        BEGIN

            IF oracle_date > max_date THEN
                RAISE_APPLICATION_ERROR( -20902,'Date too large for 32bit UNIX timestamp' );
            ELSIF oracle_date < min_date THEN
                RAISE_APPLICATION_ERROR( -20902,'Date too small for 32bit UNIX timestamp' );
            ELSE
                unix_ts := (oracle_date - unix_epoch) / (1/86400);
            END IF;

            RETURN (unix_ts);

        END;

The following query shows how it might be used:SELECT
    ename,
    TO_CHAR(hiredate, 'YYYY') AS hired_year,
    TO_CHAR(hiredate, 'YYYYMM') AS hired_month,
    TO_CHAR(hiredate, 'ddth Mon, YYYY') AS hired_pretty
    date_to_unixts(hiredate) AS hired_unixts
FROM
    emp
ORDER BY
    hiredate

It’s now easy to convert the timestamp into a formatted date, using thedate() function as you loop through the result set.

Conclusion

You have now been introduced to (or reminded of) the date time functionality available in both Oracle and PHP. You should now have a foundation for working with dates and times in your Oracle / PHP applications. You should also have a gained a fair idea of the design and implementation decisions you’ll face when handling dates.

[Ref: http://www.oracle.com/technetwork/articles/fuecks-dates-098686.html]