Wolfram Alpha is an answer engine that is great for accessing all kinds of information including statistics and data analysis, socioeconomic data, mathematics, science, etc. Did you know that you can also use Wolfram Alpha to generate QR Codes and Bar Codes for your own personal use?
A primary key uniquely identify a row in a table. One or more columns may be identified as the primary key. The values in a single column used as the primary key must be unique (like a person’s social security number). When more than one column is used, the combination of column values must be unique.
MySQL tables are easy to extend with additional columns.
The best laid plans of mice and DBAs oft go awry, so it is sometimes necessary to change the characteristics of a column after it exists and contains data. Beware whenever you make changes to your database — always make a backup first.
The SQL command in this recipe removes a column and the column’s data from an existing MySQL table.
A very cool and powerful capability in MySQL and other databases is the ability to incorporate regular expression syntax when selecting data. The regular expresion support in MySQL is extensive. This recipe reviews regular expression use in MySQL and lists the supported regular expression metacharacters.
To get the PubDate element of an RSS feed to validate, it needs to be in RFC-822 format. MySQL has flexible ways of working with dates and times which make this a simple task.
MySQL provides an easy mechanism for writing the results of a select statement into a text file on the server. Using extended options of the INTO OUTFILE nomenclature, it is possible to create a comma separated value (CSV) which can be imported into a spreadsheet application such as OpenOffice or Excel or any other applciation which accepts data in CSV format.
Sometimes every occurance of a value which may be duplicated multiple times in a result set is not needed. For example, if making a pulldown menu list of options, each option should be seen only once. The DISTINCT keyword in a select statement eliminates duplication in the result set.
If you change your mind and want to rename an existing MySQL table, with or without data in it, it is no problem. One simple command will change the table’s name.
This is a great set of two commands that allow the creation and population of a new table with the structure and data of an existing table. This provides a quick means of making a point-in-time copy of a table and is a safe, easy way to make a quick copy of a table for testing an application in development on live data without risking a production environment.
You can easily determine what version of MDAC your are running on your SQL Server by just typing a few lines into the query window. To do this:
1...342343344...502Page 343 of 502 error: Content is protected !!
