Directly insert data from java program

I’m totally new to wordpress. I have a program i built in java and up to now i’ve been using it to add data to a pligg website. Thing is the database has about 100k of records in there now and the site has started to drag after looking into it i found that it was the amount of database queries being made by the CMS asked a few people around the office and they said wordpress could solve my worries.
I had a look at the documentation on the wordpress database structure and thought i had it but not quite. The program successfully inserted records to a certain level the content and title seemed to got in right.

Tags don’t display and i’m using the simple video embeder and the data being stored is all about videos. I’m using a series of sql statements to get all the data in and i’ll paste it below.

Can anyone suggest a better way of achieving this or does wordpress have a better way to get external data in without going directly to sql (although i think it would be best to connect to the database since any php script would be called several times to insert records and the program has several threads inserting data at the same time)…

The sql i’ve got is:

sql = "INSERT INTO wp_epsez1_posts ( post_author, post_date, post_date_gmt, post_content, post_title, post_excerpt, post_status, comment_status, ping_status,post_name, to_ping, pinged, post_modified, post_modified_gmt, post_content_filtered, post_parent, guid, menu_order, post_type, post_mime_type, comment_count)"
                        + "VALUES ('1', '" + timeNow + "', '" + timeNow + "', '" + description + "', '" + title + "', '" + title + "', 'publish', 'open', 'open', '" + title.replaceAll("[^a-zA-Z0-9_]", "-").replaceAll("(.)\\1+", "$1") + "', '', '', '" + timeNow + "', '" + timeNow + "', '', '0', '', '0', 'post', '', '0');";
sql = "UPDATE wp_epsez1_posts SET guid='https://www.dibb.it/category/" + getCat(title)[0] + "/?p=" + linkId + "' WHERE post_date='" + timeNow + "'";
sql = "INSERT INTO wp_epsez1_postmeta (post_id, meta_key, meta_value) VALUES"
                            + "( '" + linkId + "', '_edit_lock', '1271217131'),"
                            + "( '" + linkId + "', '_edit_last', '1'),"
                            + "('" + linkId + "', '_p75_thumbnail', 'default.jpg'),"
                             + "('" + linkId + "', 'link_url', '"+url+"'),"
                            + "('" + linkId + "', 'ratings_users', '1'),"
                            + "('" + linkId + "', 'ratings_score', '2'),"
                            + "('" + linkId + "', 'ratings_average', '2');";
   sql = "INSERT INTO wp_epsez1_postmeta (post_id, meta_key, meta_value) VALUES ('" + linkId + "', '_videoembed_manual', '" + embedTag.replaceAll("'", "") + "')";
 sql = "INSERT INTO  wp_epsez1_terms (name ,slug)VALUES ('" + tags[i] + "',  '" + tags[i].replaceAll("[^a-zA-Z0-9_]", "-") + "');";

sql = "Select term_id from wp_epsez1_terms where slug='" + tags[i].replaceAll("[^a-zA-Z0-9_]", "-") + "' ORDER BY term_id DESC LIMIT 1";

                sql = "INSERT INTO wp_epsez1_term_relationships (object_id,term_taxonomy_id) VALUES('" + linkId + "','" + getCat(title)[1] + "')";