title: BLOB/TEXT column 'value' used in key specification without a key length
body: <p>I have developed an extension that works great on Magento until 1.6 (I'm trying Enterprise ed, and I would assume that Community has the same problem, as it has the same code). In my install script, I'm calling <code>$installer-&gt;createEntityTables($this-&gt;getTable('alphanum/info'));</code>. The installation goes just fine until it comes to the _text entity table. It crashes there! It turns out when I log the sql and run it through PHPmyadmin, this is the error: <code>BLOB/TEXT column 'value' used in key specification without a key length</code>. I looked at there code, and this is what is trying to generate a index on the value column: </p>
  
  <pre><code>-&gt;addIndex($this-&gt;getIdxName($eavTableName, array('attribute_id', 'value')),
       array('attribute_id', 'value'))
  -&gt;addIndex($this-&gt;getIdxName($eavTableName, array('entity_type_id', 'value')),
       array('entity_type_id', 'value'))
  </code></pre>
  
  <p>It doesn't have any <code>if</code> statements to make sure it is not of type text. Is there something that I am missing? Do I need to change my DB configuration? Could this be a bug?</p>
  
  <p>I have been kicking around putting an <code>if</code> statement around it (breaking it out of the parent chain) to get the extension in. That should nicely do it. I looked at the previous rev (1.5.something), and it didn't have that index in there. I just can't figure out why it didn't cause a lot of problem when they added it. Makes me wonder if it's my problem somehow?</p>
  
  <p>Don't know if this would help to include the SQL that Magento created:</p>
  
  <pre><code>CREATE TABLE `alphanum_info_text` (
    `value_id` int NOT NULL auto_increment COMMENT 'Value Id',
    `entity_type_id` smallint UNSIGNED NOT NULL default '0' COMMENT 'Entity Type Id',
    `attribute_id` smallint UNSIGNED NOT NULL default '0' COMMENT 'Attribute Id',
    `store_id` smallint UNSIGNED NOT NULL default '0' COMMENT 'Store Id',
    `entity_id` int UNSIGNED NOT NULL default '0' COMMENT 'Entity Id',
    `value` text NOT NULL COMMENT 'Attribute Value',
    PRIMARY KEY (`value_id`),
    INDEX `IDX_ALPHANUM_INFO_TEXT_ENTITY_TYPE_ID` (`entity_type_id`),
    INDEX `IDX_ALPHANUM_INFO_TEXT_ATTRIBUTE_ID` (`attribute_id`),
    INDEX `IDX_ALPHANUM_INFO_TEXT_STORE_ID` (`store_id`),
    INDEX `IDX_ALPHANUM_INFO_TEXT_ENTITY_ID` (`entity_id`),
    INDEX `IDX_ALPHANUM_INFO_TEXT_ATTRIBUTE_ID_VALUE` (`attribute_id`, `value`),
    INDEX `IDX_ALPHANUM_INFO_TEXT_ENTITY_TYPE_ID_VALUE` (`entity_type_id`, `value`),
    CONSTRAINT `FK_ALPHANUM_INFO_TEXT_ENTITY_ID_EAV_ENTITY_ENTITY_ID` FOREIGN KEY     (`entity_id`) REFERENCES `eav_entity` (`entity_id`) ON DELETE CASCADE ON UPDATE CASCADE,
    CONSTRAINT `FK_ALPHA_NUM_TEXT_ENTT_TYPE_ID_EAV_ENTT_TYPE_ENTT_TYPE_ID` FOREIGN KEY (`entity_type_id`) REFERENCES `eav_entity_type` (`entity_type_id`) ON DELETE CASCADE ON UPDATE CASCADE,
    CONSTRAINT `FK_ALPHANUM_INFO_TEXT_STORE_ID_CORE_STORE_STORE_ID` FOREIGN KEY (`store_id`) REFERENCES `core_store` (`store_id`) ON DELETE CASCADE ON UPDATE CASCADE
  ) COMMENT='Eav Entity Value Table' ENGINE=INNODB charset=utf8 COLLATE=utf8_general_ci
  </code></pre>