Help:Expression table

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Database layout

Expression table

Tracks all existing expressions, as well as expressions that have been deleted. A expression is a specific word (e.g. "word") in a specific language (e.g. "English").

+-----------------------+------------------+------+-----+---------+-------+
| Field                 | Type             | Null | Key | Default | Extra |
+-----------------------+------------------+------+-----+---------+-------+
| expression_id         | int(10) unsigned | NO   | MUL | NULL    |       | 
| spelling              | varchar(255)     | YES  |     | NULL    |       | 
| language_id           | int(10)          | NO   | MUL | 0       |       | 
| add_transaction_id    | int(11)          | NO   | MUL | NULL    |       | 
| remove_transaction_id | int(11)          | YES  | MUL | NULL    |       | 
+-----------------------+------------------+------+-----+---------+-------+

Fields

expression_id 

A number that identifies the expression

spelling 

A string corresponding to the word of that expression, e.g. "word".

language_id 

The language of that expression. See Language table.

add_transaction_id 

Indicates when and by who the expression was added. See Transactions table.

remove_transaction_id 

Indicates when and by who the expression was removed. NULL if the expression is still in use

. Actually, this field is currently not touched when an expression is removed (this is not a feature, it is a bug). Instead, the Syntrans table should be consulted (see below) to know if an expression has been removed.

Sample MySQL code

The following code will return all the valid (i.e. not removed) words in English (language_id=85):

select distinct spelling

from uw_expression, uw_syntrans

where uw_expression.expression_id = uw_syntrans.expression_id

and uw_expression.language_id = 85

and uw_syntrans.remove_transaction_id IS NULL;

However, the following code will give a wrong result (more results than expected):

select spelling

from uw_expression

where uw_expression.language_id = 85

and uw_expression.remove_transaction_id IS NULL;