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Simple MySQL Stored Procedure

admin — Sat, 14 Feb 2009 16:39:04 +0000

Here's a simple stored procedure I find myself using for MySQL over and over again. If you use a person's email address as a database key, you may need to occasionally update their email address, and as such, you should update all references. Here's a simple stored procedure to accomplish this:

DELIMITER $$

DROP PROCEDURE IF EXISTS changeEmail $$
CREATE PROCEDURE changeEmail (oldEmail varchar(100), newEmail varchar(100))
BEGIN
 -- First check our arguments and that the old email exists
 IF (oldEmail IS NOT NULL) AND (newEmail IS NOT NULL) AND
    (EXISTS (SELECT * FROM users WHERE email=oldEmail))
 THEN
   -- Update all references of the old email to the new one here
   UPDATE users set email=newEmail WHERE email=oldEmail LIMIT 1;
   UPDATE billing set email=newEmail WHERE email=oldEmail;
   UPDATE cards set email=newEmail WHERE email=oldEmail;
   UPDATE orders set user_email=newEmail WHERE user_email=oldEmail;
 END IF;
END $$

DELIMITER ;

Enjoy!

App.config Settings for a Project with no Output

admin — Fri, 17 Oct 2008 19:58:31 +0000

Sometimes more than just connection strings need to be stored to a settings or configuration file of some kind. If you are building a mult-tier application and your project is a class library with no run-able code, you can't just throw settings into an app.config file. Likewise, you wouldn't want to put your tier-specific settings in a different project just because that project contains the output (and the app.config).

A simple way around this problem is to create a settings file for your project. To do so, right click on your project and select "Properties"

Navigate to the "Settings" tab and click the link to create a new settings file

Add the application specific parameters to your settings file via the designer. Save and rebuild your project.

To use your settings, reference them via the following syntax:

Properties.Settings.Default.MySetting

Enjoy!

SQL Server Find Text in Any Field

admin — Fri, 17 Oct 2008 13:06:40 +0000

In working with SQL server 2005, I came across this useful query which will loop through every table and every field in a database searching for specified text. This can really come in handy when you're debugging someone else's un-documented database and you know the text, but you're not sure where it is stored in the database. Note that this will store the results of this query in a table called "Results", so if you have a table with that name, you'll want to rename the table below. Also be sure to change your search criteria... Enjoy!

DROP TABLE #Results
CREATE TABLE #Results (ColumnName nvarchar(370), ColumnValue nvarchar(3630))
SET NOCOUNT ON
 
DECLARE @TableName nvarchar(256), @ColumnName nvarchar(128), @SearchStr2 nvarchar(110)
SET  @TableName = ''
SET @SearchStr2 = QUOTENAME('','''')
 
WHILE @TableName IS NOT NULL
BEGIN
  SET @ColumnName = ''
  SET @TableName =
  (
    SELECT MIN(QUOTENAME(TABLE_SCHEMA) + '.' + QUOTENAME(TABLE_NAME))
    FROM   INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE = 'BASE TABLE'
    AND QUOTENAME(TABLE_SCHEMA) + '.' + QUOTENAME(TABLE_NAME) > @TableName
    AND OBJECTPROPERTY(
      OBJECT_ID(
        QUOTENAME(TABLE_SCHEMA) + '.' + QUOTENAME(TABLE_NAME)
      ), 'IsMSShipped'
    ) = 0
  )
 
  WHILE (@TableName IS NOT NULL) AND (@ColumnName IS NOT NULL)
  BEGIN
    SET @ColumnName =
    (
      SELECT MIN(QUOTENAME(COLUMN_NAME))
      FROM INFORMATION_SCHEMA.COLUMNS
      WHERE TABLE_SCHEMA = PARSENAME(@TableName, 2)
      AND TABLE_NAME  = PARSENAME(@TableName, 1)
      AND DATA_TYPE IN (
        'char', 'varchar', 'nchar', 'nvarchar', 'uniqueidentifier', 'smallint', 'identity'
      )
      AND QUOTENAME(COLUMN_NAME) > @ColumnName
    )
 
    IF @ColumnName IS NOT NULL
    BEGIN
    INSERT INTO #Results
    EXEC
    (
      'SELECT ''' + @TableName + '.' + @ColumnName + ''', LEFT(' + @ColumnName + ', 3630)
      FROM ' + @TableName + ' (NOLOCK) ' +
      ' WHERE ' + @ColumnName + ' LIKE ' + @SearchStr2
    )
    END
  END
END
 
SELECT ColumnName, ColumnValue FROM #Results

MySQL Blob Insert Error

admin — Fri, 04 Jan 2008 21:54:23 +0000

When using MySQL to store things such as files, it is best to use a blob field. If you're using a blob field, but having trouble with inserting some data into it (like a file), you might want to check the MySQL environment varibale max_allowed_packet. The max_allowed_packet variable can be found in your configuration file (usually /etc/my.cnf), and is usually set to something around 1 MB. If you try to insert a binary file larger than 1MB, the MySQL insert will fail. All that's needed, is to change to max_allowed_packet to something larger, then, restart MySQL: