Archive for February, 2013

Postgres: Get table and field names from a given schema

Friday, February 8th, 2013

I work with a large Postgres install that has many hundreds of schemas. there are times that I need to find a list of tables and fields from a specific schema for a web application that I am developing.

This will return the list of table names within the giving schema:

select relname 
from pg_stat_user_tables 
WHERE schemaname='schema1';

Then to get the given field names from the table that I have chosen:

select column_name 
from information_schema.columns 
where table_name='mytable';

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Posted in Programming, SQL | No Comments »

How to include Javascript on a web page

Wednesday, February 6th, 2013

There are three ways to include Javascript files on a website. You can use scripts placed in the head element, scripts placed within the body element or you can include an external file.

The <script> tag is used to contain the Javascript code when you are placing it within the web page.

Example of code within the <head> tag:

 <!DOCTYPE html>
<html>
<head>
<title>Javascript in Head tag</script>
<script language="javascript" type="text/javascript" >
     document.write("Hello, World!");
</script>
</head>
<body>
</body>
</html>

When you are expecting to output directly into the page it is helpful to place the script in the
<body> tag.

<!DOCTYPE html>
<html>
<head>
<title>Javascript in Body tag</script>
<script>

</script>
</head>
<body>
<script language="javascript" type="text/javascript" >
  document.write("Hello, World!");
</script>
</body>
</html>

And when you are including an external script like jQuery or a custom script, you will use an
tag in the head with a src identifier to specify the file. Where you might reference the file in an onload or some other scripting within the page.

<!DOCTYPE html>
<html>
<head>
<title>Javascript in External file</script>
<script language="javascript" type="text/javascript" src="somefile.js" > </script>
</head>
<body onload="callsomefile();" >
</body>
</html>

There is also the possibility that someone will have turned off Javascript and this is where the <noscript> tag can be used to either display the site designed with no scripting involved or inform the user that they cannot use the site unless Javascript is enabled.

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Posted in html, Programming, Web Design | No Comments »