Querying for multiple many-to-many associates in MySQL

Background

My program is storing a series of objects, a set of tags, and the many-to-many associations between tags and objects, in a MySQL database. To give you an idea of the structure:

CREATE TABLE objects (
    object_id INT PRIMARY KEY,
    ...
);
CREATE TABLE tags (
    tag_name VARCHAR(32) NOT NULL
);
CREATE TABLE object_tags (
    object_id INT NOT NULL,
    tag_name VARCHAR(32) NOT NULL,
    PRIMARY KEY (object_id, tag_name)
);

Problem

I want to be able to query for all objects that are tagged with all of the tags in a given set. As an example, let's say I have a live tree, a dead flower, an orangutan, and a ship as my objects, and I want to query all of those tagged living and plant. I expect to receive a list containing only the tree, assuming the tags match the characteristics of the objects.

Current Solution

Presently, given a list of tags T1, T2, ..., Tn, I am solving the problem as follows:

1. Select all object_id columns from the object_tags table where tag_name is T1.
2. Join the result of (1) with the object_tags table, and select all object_id columns where tag_name is T2.
3. Join the result of (2) with the object_tags table again, and select all object_id columns where tag_name is T3.
4. Repeat as necessary for T4, ..., Tn.
5. Join t开发者_StackOverflow社区he result of (4) with the objects table and select the additional columns of the objects that are needed.

In practice (using Java), I start with the query string for the first tag, then prepend/append the string parts for the second tag, and so on in a loop, before finally prepending/appending the string parts that make up the overall query. Only then does the string actually get passed into a PreparedStatement and get executed on the server.

Edit: Expanding on my example from above, using this solution I would issue the following query:

SELECT object_id FROM object_tags JOIN (
    SELECT object_id FROM object_tags WHERE tag_name='living'
) AS _temp USING (object_id) WHERE tag_name='plant';

Question

Is there a better solution to this problem? Although the number of tags is not likely to be large, I am concerned about the performance of this solution, especially as the database grows in size. Furthermore, it is very difficult to read and maintain the code, especially when the additional concerns/constraints of the application are thrown in.

I am open to suggestions at any level, although the languages (MySQL and Java) are not variables at this point.

I don't know about the performance of this solution, but you can simplify by using pattern matching in MySql to match a set of pipe-delimited tags (or any delimiter). This is a solution I've used before for similar applications with tag tables (@match would be a variable passed in by your Java code, I've harded coded a value for demonstration):

set @match = 'living|plant';
set @numtags =
    length(@match) - length(replace(@match, '|', '')) + 1;

select * from objects o
where @numtags =
(
    select count(*) from object_tags ot
    where concat('|',@match,'|')
        like concat('%|',ot.tag_name,'|%')
    and ot.object_id = o.object_id
)

Here is a working demo: http://sqlize.com/0vP6DgQh0j