May I suggest that you consult the docs before posting here?

http://docs.elgg.org/wiki/DatabaseSchema

Sorry, I am quite poor in that. I can't see any info about telling where are the data stored. How or where can I see all the data in the database? Do I need to write code to create a view page to list out all the data by myself? It is so inconvinient... sad.

have you checked the table called objects_entity? most of your site's contents are stored as elgg objects

@Cim. Thanks for the reply. Objects_entity table has 3 fields, guid field has the records of 4,6,7.8... until 37. Meaning it has 39 rows, but other 2 fields (title and description) are empty, I cannot see any words on the 39 rows of the 2 fields.

I saw elgg_users_entity has 30 users only, but the records of guid field keep skipping from 1 to 20, 20 to 150, 150 to 311... There are 30 users only, I though the GUID should be until 30 only, but the GUID is not 30, but it is 700 already!!! I am wondering 20 big int is enough for all facebook users? Why don't Elgg seperate the GUID for user, blog, group, message seperately? It can save more id for each entity.

I saw elgg_groups_entity has 1 record.

May I know where is the table that store the records of :

1 - Messenging system between users?

2 - The Blogs title and body?

3 - The wire and replies?

4 - The relationship between friends and users?

@Zac - give it up ;'-) From your questions it seems that you are not yet too comfortable poking around and messing with the data model. There is much more to searching for / locating various metadata owned by PlugIns, etc as you have listed. The GUID# situation you mentioned is irrelevant - that's how it is supposed to be ;-) "Why don't Elgg gives GUID for user, blog, group, message seperately?..." Elgg does do that ! LOLZ ;-P

May I know how can I see all the blog post and title metadata records?

where can I see all te records?

Oki ;-)
My 99c worth
An example of a Blog
with all relevant attributes
and metadata fields ->

entities

id type   subtype
8  object blog

  
entities (type=object subtype=8)
guid type   subtype owner_guid site_guid container_guid

36   object 8       2          1         2           

objects_entity
guid title       description

36      Blog Test 1 <p>Blog Test 1...</p>

metadata
id     entity_guid  name_id value_id value_type owner_guid

638 36           24      120      text       2
634 36           52      171      text       2
635 36              52      172      text       2
637 36          124      118      text       2
636 36          134      135      text       2

metastring
 id string

 24 website
120 categ3
 52 tags
171 tag2
172 tag3
124 universal_categories
118 categ1
134 comments_on
135 on

objects_entity
guid title       description

36      Blog Test 1 <p>Blog Test 1...</p>

why you objects_entity table has the records inside title and decription but mine don't have? I saw the records are empty. There are many records on GUID fields, but there is no record on title and description fields. So many blogs are created on my website http://plekz.com/ but I can't see any record on the database. May I know where they keep the data?

Oh damn how stupid is me!!!! There are 4 pages on the table, I go to page 4 only can see the records!!! How silly is me!!! OMG!!! Anyway I need to thanks to Cim and DhrupDeScoop , if without you both, I will not focus on that table and I will not figure this out!!! Thank you !!!