The difference is purely in the maximum value which can be stored (18,446,744,073,709,551,615 for the bigint(20) and 4,294,967,295 for the int(10), I believe), as per the details on the MySQL [Numeric Types][1] manual page.

Incidentally, the use of (20) and (10) is largely irrelevant unless you&#39;re using ZEROFILL. (i.e.: It doesn&#39;t actually change the size of the number stored - that&#39;s all down to the type.)

However, in practical terms it should be noted that you&#39;re not likely to hit either of these limits any time soon, unless you&#39;re a ***really*** active blogger.


  [1]: http://dev.mysql.com/doc/refman/5.0/en/numeric-type-overview.html

The only difference is the range of the type. `INT` is a 32-bit long while `BIGINT` is 64-bit long, therefore it can store much larger numbers like `123456789123456789` (which cannot be stored as `INT`).

Here&#39;s a full list of MySQL integer types: http://dev.mysql.com/doc/refman/5.0/en/numeric-types.html

I have a euclidean vector `a` sitting at the coordinates `(0, 1)`.
I want to rotate `a` by 90 degrees (clockwise) around the origin: `(0, 0)`.

If I have a proper understanding of how this should work, the resultant (x, y) coordinates after the rotation should be `(1, 0)`.
If I were to rotate it by 45 degrees (still clockwise) instead, I would have expected the resultant coordinates to be `(0.707, 0.707)`.

	theta = deg2rad(angle);

	cs = cos(theta);
	sn = sin(theta);
	
	x = x * cs - y * sn;
	y = x * sn + y * cs;

Using the above code, with an `angle` value of 90.0 degrees, the resultant coordinates are: `(-1, 1)`.
And I am so damn confused.
The examples seen in the following links represent the same formula shown above surely?

What have I done wrong?
Or have I misunderstood how a vector is to be rotated?

2D Euclidean vector rotations

I&#39;m using Node.js and wanting to incorporate CoffeeScript into my workflow. I have two use-cases:

 1. I want to be able to write JavaScript files which `require()` CoffeeScript modules
 2. I want to be able to load CoffeeScript modules from within the node REPL

**For case #1:** I can just compile from `.coffee` to `.js` and `require()` the `.js` module, as a workaround. 

**For case #2:** Right now I&#39;m `eval()`ing the output of `coffee-script.compile()`.

Is there a better, more unified way to do this?

require()&#39;ing a CoffeeScript file from a JavaScript file or REPL

I have been using int(10) and just noticed that Wordpress uses bigint(20) - What is different to use bigint(20) and int(10) for id auto increment? Which one should I use for id column?

    `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,

Vs
    
    `id` int(10) unsigned NOT NULL AUTO_INCREMENT,

Thanks.

MySQL: bigint Vs int

I have been using int(10) and just noticed that Wordpress uses bigint(20) - What is different to use bigint(20) and int(10) for id auto increment? Which one should I use for id column?
<pre><code class="hljs language-arduino">`id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
</code></pre>
Vs
<pre><code class="hljs language-c">`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
</code></pre>
Thanks.

I have my database properly set to UTF-8 and am dealing with a database containing Japanese characters.  If I do SELECT *... from the mysql command line, I properly see the Japanese characters.  When pulling data out of the database and displaying it on a webpage, I see it properly.

However, when viewing the table data in phpMyAdmin, I just see garbage text.  ie.

&#231;&#167;&#227;&#175;&#230;—&#165;&#230;œ&#172;&#230;–™&#231;†&#227;Œ&#229;&#165;&#189;&#227;&#227;&#167;&#227;™&#227;€‚&#230;—&#165;&#230;œ&#172;&#230;–™&#231;†&#227;‚...

How can I get phpMyAdmin to display the characters in Japanese?

The character encoding on the HTML page is set to UTF-8.

Edit:

I have tried an export of my database and opened up the .sql file in geany.  The characters are still garbled even though the encoding is set to UTF-8.  (However, doing a mysqldump of the database also shows garbled characters).

The character set is set correctly for the database and all tables (&#39;latin&#39; is not found anywhere in the file)

    CREATE DATABASE `japanese` DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;

I have added the lines to my.cnf and restarted mysql but there is no change.  I am using Zend Framework to insert data into the database.

I am going to open a bounty for this question as I really want to figure this out.

How to display UTF-8 characters in phpMyAdmin?

I want to do a *[full outer join][1]* in MySQL. Is this possible? Is a *full outer join* supported by MySQL?

  [1]: https://en.wikipedia.org/wiki/Join_(SQL)#Full_outer_join




How can I do a FULL OUTER JOIN in MySQL?

I realize a couple of basic differences between the two, i.e.

1. EC2 is going to be cheaper

2. RDS I wouldn&#39;t have to do maintenance

Other than those two, are there any advantages to running my database from RDS as opposed to a separate EC2 server acting as a MySQL server. Assuming similar instance sizes, are both going to run into the same limitations in terms of being able to handle a load?

To give you a little bit more info about my use, I&#39;ve got a database, nothing too big or anything (biggest table 1 million rows), just high SELECT volume.

What are the respective advantages/limitations of Amazon RDS vs. EC2 with MySQL?

Any good rules of thumb on how to decide which of the two to use?

And, if you take over an Sqlite database, and the system is expected to &quot;get much larger&quot;, how to decide whether to stick with it or move to MySql?

Sqlite or MySql? How to decide?

i would like to do a find and replace inside an entire database not just a table.

How can i alter the script below to work?

     update [table_name] set [field_name] = replace([field_name],&#39;[string_to_find]&#39;,&#39;[string_to_replace]&#39;);

Do i just use an asterix?

     update * set [field_name] = replace([field_name],&#39;[string_to_find]&#39;,&#39;[string_to_replace]&#39;);

Find and replace entire mysql database

I&#39;m writing an application that doesn&#39;t necessarily need **scaling abilities** as it won&#39;t be collecting large amounts data at the beginning. (However, if I&#39;m lucky, I could down the road potentially.)

I will be running my web server and database on the same box (for now).

That being said, I am looking for performance and efficiency. 

The main part of my application will be loading blog articles. Using an RDBMS (MySQL) I will make 6 queries (2 of the queries being joins), just to load a single blog article page. 

    select blog
    select blog_album
    select blog_tags
    select blog_notes
    select blog_comments (join with users)
    select blog_author_participants (join with users)

However, with [MongoDB][1] I can de-normalize and flatten 6 tables into just 2 tables/collections and minimizes my queries to potentially just one 1 query,

    users
    blogs
        -&gt;blog_album
        -&gt;blog_tags        
        -&gt;blog_notes
        -&gt;blog_comments
        -&gt;blog_author_participants

Now, going with the MongoDB schema, there will be some data redundancy. However, hard drive space is cheaper than CPU/servers. 

1.) Would this be a good scenario to use MongoDB? 

2.) Do you only benefit in performance using MongoDB when scaling beyond a single server?

3.) Are there any durability risks using MongoDB? I hear that there is potential for loss of data while performing inserts - as insert are written to memory first, then to the database.

4.) Should this stop me from using MongoDB in production?

  [1]: http://en.wikipedia.org/wiki/MongoDB


When to use MongoDB

I need to add proper `index` to my tables and need some help.

I&#39;m confused and need to clarify a few points:

- Should I use index for `non-int` columns? Why/why not

- I&#39;ve read a lot about `clustered` and `non-clustered` index yet I still can&#39;t decide when to use one over the other. A good example would help me and a lot of other developers. 

I know that I shouldn&#39;t use indexes for columns or tables that are often updated. What else should I be careful about and how can I know that it is all good before going to test phase?

Difference between clustered and nonclustered index

My requirements are:

 - Need to be able to dynamically add User-Defined fields of any data type
 - Need to be able to query UDFs quickly
 - Need to be able to do calculations on UDFs based on datatype 
 - Need to be able to sort UDFs based on datatype

Other Information:

 - I&#39;m looking for performance primarily
 - There are a few million Master records which can have UDF data attached
 - When I last checked, there were over 50mil UDF records in our current database
 - Most of the time, a UDF is only attached to a few thousand of the Master records, not all of them
 - UDFs are not joined or used as keys. They&#39;re just data used for queries or reports

Options:

 1. Create a big table with StringValue1, StringValue2... IntValue1, IntValue2,... etc. I hate this idea, but will consider it if someone can tell me it is better than other ideas and why.

 2. Create a dynamic table which adds a new column on demand as needed. I also don&#39;t like this idea since I feel performance would be slow unless you indexed every column.

 3. Create a single table containing UDFName, UDFDataType, and Value. When a new UDF gets added, generate a View which pulls just that data and parses it into whatever type is specified. Items which don&#39;t meet the parsing criteria return NULL.

 4. Create multiple UDF tables, one per data type. So we&#39;d have tables for UDFStrings, UDFDates, etc. Probably would do the same as #2 and auto-generate a View anytime a new field gets added

 5. XML DataTypes? I haven&#39;t worked with these before but have seen them mentioned. Not sure if they&#39;d give me the results I want, especially with performance.

 6. Something else? 

How to design a database for User Defined Fields?

I am building a custom events system, and if you have a repeating event that looks like this:

Event A repeats every 4 days starting on March 3, 2011

or 

Event B repeats every 2 weeks on Tuesday starting on March 1, 2011

How can I store that in a Database in a way that would make it simple to lookup. I don&#39;t want performance issues if there are a large number of events, and I have to go through each and every one when rendering the calendar.

Calendar Recurring/Repeating Events - Best Storage Method

Here&#39;s three best practices I try to follow when naming tables:

 - Never name a table with plural (such as &quot;users&quot;)
 - Never name a table using a reserved keyword (such as &quot;user&quot;)
 - Never prefix your table name with &quot;tbl&quot; or some other object type prefix

Keeping all this in mind, how do you recommend naming the table that will hold user identities?

What is the best practice in naming your &quot;user&quot; table?

So I have an `IEnumerable&lt;string&gt;` which can contain values that can be parsed as `int`, as well as values that cannot be.

As you know, `Int32.Parse` throws an exception if a string cannot be changed to an int, while `Int32.TryParse` can be used to check and see if the conversion was possible without dealing with the exception. 

So I want to use a LINQ query to one-liner parse those strings which can be parsed as int, without throwing an exception along the way. I have a solution, but would like advice from the community about whether this is the best approach.

Here&#39;s what I have:

    int asInt = 0;
    var ints = from str in strings
               where Int32.TryParse(str, out asInt)
               select Int32.Parse(str);

So as you can see, I&#39;m using `asInt` as a scratch space for the call to `TryParse`, just to determine if `TryParse` would succeed (return bool). Then, in the projection, I&#39;m actually performing the parse. That feels ugly.

Is this the best way to filter the parseable values in one-line using LINQ?

Select parsed int, if string was parseable to int

I just want to know if there&#39;s a better solution to parse a number from a character in a string (assuming that we know that the character at index n is a number).

    String element = &quot;el5&quot;;
    String s;
    s = &quot;&quot;+element.charAt(2);
    int x = Integer.parseInt(s);
    
    //result: x = 5

(useless to say that it&#39;s just an example)

Java: parse int value from a char

Is there a way to test a range without doing this redundant code:

    if ($int&gt;$min &amp;&amp; $int&lt;$max)

?

Like a function:

    function testRange($int,$min,$max){
        return ($min&lt;$int &amp;&amp; $int&lt;$max);
    }

usage:
    
    if (testRange($int,$min,$max)) 

?

Does PHP have such built-in function? Or any other way to do it?


How to check if an integer is within a range?

Given a number:

    int number = 1234;

Which would be the &quot;best&quot; way to convert this to a string:

    String stringNumber = &quot;1234&quot;;

----------


&lt;sup&gt;
I have tried searching (googling) for an answer but no many seemed &quot;trustworthy&quot;.
&lt;/sup&gt;

Java - Convert integer to string

How do I convert an integer to a hex string in [C++][1]?

I can find some ways to do it, but they mostly seem targeted towards C. It doesn&#39;t seem there&#39;s a native way to do it in C++. It is a pretty simple problem though; I&#39;ve got an `int` which I&#39;d like to convert to a hex string for later printing. 

  [1]: http://en.wikipedia.org/wiki/C%2B%2B




Integer to hex string in C++

How would I go about doing arithmetic, + - / * % !,  with arbitrarily large integers without using `java.math.BigInteger`?

For instance, the factorial of 90 returns 0 in Java.
I would like to be able to solve that.

How to handle very large numbers in Java without using java.math.BigInteger

I&#39;m transferring raw data like `[{id: 12000000000002539, Name: &quot;Some Name&quot;}]` and I&#39;m getting the object `[{id: 12000000000002540, Name: &quot;Some Name&quot;}]` after parsing, for now server side converting id into string seems to help.
But is there a better way to transfer bigint data correctly?

JSON transfer of bigint: 12000000000002539 is converted to 12000000000002540?

I looked into this [stackoverflow question relating to Big Integer][1] and specifically I do not understand this line (the words in italics):

&gt; In the BigInteger class, *I have no limits* and there are some helpful
&gt; functions there but it is pretty depressing to convert your beautiful
&gt; code to work with the BigInteger class, specially when primitive
&gt; operators don&#39;t work there and you must use functions from this class.

I don&#39;t know what I am missing but to represent something that has no limit you would require infinite memory ? Whats is the trick here ?

[1]:https://stackoverflow.com/questions/2776400/biginteger-or-not-biginteger

What does BigInteger having no limit mean?

&gt; **Possible Duplicate:**  
&gt; [What does BigInteger having no limit mean?](https://stackoverflow.com/questions/12088436/what-does-biginteger-having-no-limit-mean)  

&lt;!-- End of automatically inserted text --&gt;

The Javadoc for `BigInteger` does not define any maximum or minimum.  However, it does say:

(emphasis added)
&gt; Immutable **arbitrary-precision** integers

Is there such a maximum, even in theory?  Or is the way `BigInteger` operates fundamentally different, such that there is in reality *no* maximum except for the amount of memory available on the computer?

Is there an upper bound to BigInteger?

I&#39;m trying to read some really big numbers from standard input and add them together.

However, to add to BigInteger, I need to use `BigInteger.valueOf(long);`:

    private BigInteger sum = BigInteger.valueOf(0);

    private void sum(String newNumber) {
        // BigInteger is immutable, reassign the variable:
        sum = sum.add(BigInteger.valueOf(Long.parseLong(newNumber)));
    }

That works fine, but as the `BigInteger.valueOf()` only takes a `long`, I cannot add numbers greater than `long`&#39;s max value (9223372036854775807).

Whenever I try to add 9223372036854775808 or more, I get a NumberFormatException (which is completely expected).

Is there something like `BigInteger.parseBigInteger(String)`?


How do I convert a String to a BigInteger?

How do I add `auto_increment` to an existing column of a MySQL table?


How to add AUTO_INCREMENT to an existing column?

I would like to force the auto increment field of a table to some value, I tried with this:

    ALTER TABLE product AUTO_INCREMENT = 1453

AND 

    ALTER SEQUENCE product  RESTART WITH 1453;
    ERROR:  relation &quot;your_sequence_name&quot; does not exist

I&#39;m new to postgres :( 

I have a table `product` with `Id` and `name` field



Reset auto increment counter in postgres

I have a table set up that currently has no primary key. All I need to do is add a `primary key, no null, auto_increment`.

I&#39;m working with a `Microsoft SQL Server` database. I understand that it can&#39;t be done in a single command but every command I try keeps returning syntax errors.

edit ---------------

I have created the primary key and even set it as not null. However, I can&#39;t set up the `auto_increment`.

I&#39;ve tried:

    ALTER TABLE tableName MODIFY id NVARCHAR(20) auto_increment
    ALTER TABLE tableName ALTER COLUMN id NVARCHAR(20) auto_increment
    ALTER TABLE tableName MODIFY id NVARCHAR(20) auto_increment
    ALTER TABLE tableName ALTER COLUMN id NVARCHAR(20) auto_increment

I&#39;m using `NVARCHAR` because it wouldn&#39;t let me set `NOT NULL` under int

How do I add a auto_increment primary key in SQL Server database?

Wondering if there is a shorthand version to insert a new record into a table that has the primary key enabled? (i.e. not having to include the key column in the query)
Lets say the key column is called ID, and the other columns are Fname, Lname, and Website

    $query = &quot;INSERT INTO myTable VALUES (&#39;Fname&#39;, &#39;Lname&#39;, &#39;Website&#39;)&quot;;

PHP mySQL - Insert new record into table with auto-increment on primary key

I have a table in PostgreSQL with many columns, and I want to add an auto increment primary key.

I tried to create a column called `id` of type `BIGSERIAL` but pgadmin responded with an error:

&gt;     ERROR: sequence must have same owner as table it is linked to.

Does anyone know how to fix this issue?  How do I add or create an auto-incrementing primary key in PostgreSQL without recreating the table?

Content Type	Original Author	Original Content on Stackoverflow
Question	Run	View Question on Stackoverflow
Solution 1 - Mysql	John Parker	View Answer on Stackoverflow
Solution 2 - Mysql	Crozin	View Answer on Stackoverflow

MySQL: bigint Vs int

Mysql Problem Overview

Mysql Solutions

Solution 1 - Mysql

Solution 2 - Mysql

require()'ing a CoffeeScript file from a JavaScript file or REPL

2D Euclidean vector rotations

Attributions