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Yes. I confirmed that right-clicking on a join line does allow deleting or editing. If I understand you correctly, no, relationship definitions should not be part of the back-end. The table relationship is defined for the back-end by the front-end through the SQL statements. For example, I have a table of suppliers, with names and addresses and other contact information. This table is related to almost all of my database (main) tables. Additionally, each "main" table has its own set of table relationships with other (sub?) tables, most of which are for selecting options with a join. Each record of these option tables contains a primary key and a text field for the option. For example, I have a table of statuses for the item in the main table record. An integer foreign key in the main table contains a primary key value corresponding to the text element of the statuses table record. That way, I am only storing an integer (key value) in the main table, rather than the option text, and with no repeated option text. It also standardizes the option texts. All of these multiple relationships must be defined by me - ergo it needs to be in the front-end.
Hope this helps clarify this.
Girvin Herr

Tom Davies wrote:
Hi :)
Can you right-click on a relationship's join-line and edit it's properties? Shouldn't the relationships be part of the back-end rather than defined in the front-end? Regards from Tom :)

From: Dan Lewis <>
To: Sent: Wednesday, 9 January 2013, 4:14
Subject: Re: [libreoffice-users] Re: Base scenario

Comment inline below.


On 01/08/2013 07:07 PM, Girvin R. Herr wrote:
Have you actually drawn any relationships?  Base will not do that for you.  Just adding the tables 
in the 'Relationships Window' will not create the relationships automagically.  You must click and 
hold on the one table element (remote key) and drag over to the related table's element (primary 
key), then release the mouse button.  Base will then draw a line between the two.  Note, the order 
of the drag is important.  It determines the type of join. Joins are confusing to me too, so I 
can't help much there.  I had to experiment with the direction to get it to work right.  I think it 
was remote key to primary key, but I am not sure of that any more.

Warning!  The way the SQL language is set up, if either of the ends of a join (relationship) is NULL, then the record will be discarded and 
not show up in your result set.  No warnings, no errors.  Data records will just be missing.  IMHO, this is stupid (my mantra is: 
"thou shall not lose data"), but that is how the SQL language was set up.  So, make sure any joined data elements in all of your 
table records are not NULL.  Note that NULL is not zero (0) and vice-versa!  NULL means that there is no data in the record element.  I use 
a lot of remote keys in my database main tables that point to primary keys (options) in other tables.  In those other tables, I have made 
it a point to make the data elements of the first record to be "-", which is my equivalent of unknown, just to have something to 
select that is not NULL.  You could probably use a blank (" "), but I prefer seeing the "-" in forms and reports.  Most 
times in reports, it is hard
 to see anyway.  Seeing the "-" tells me the field is not NULL.
Hope this helps.
Girvin Herr

      These statements about joins do not seem to be quite correct. What you are describing is an 
Inner Join: you will only see the rows of data in which both the foreign (remote) key and the 
primary key have a value.
     Suppose we have two tables A and B and that the foreign (remote) key is in table A and the 
primary key is in table B.
    Example 1: table A Left Outer Join table B. The output (result set) for this contains all the 
fields in table A and their values on the left side of the combined table. The right side contains 
all the fields in Table B. The rows in which the primary key value matches the foreign key value, 
data from both table appear in the output. However, where there is no primary key value in table B 
that matches the foreign key value in table A, all the fields from table B for that row will be 
     Example 2: table A Right Outer Join table B. The output for this contains all the fields in 
table B and their values on the right side. For each output row in which the foreign key does not 
have a value that matches any value of the primary key, the fields in the left side of it will be 
     Example 3: table A Cross Join table B. This is also referred to as a Cartesian Product. In 
this case, each row of table A is joined to all the rows of table B. This contains all of the 
possible combinations of combining both tables. Usually, some rows of the output will have the 
table A fields all showing NULL while others will have the fields of table B showing all NULL.

Ian Whitfield wrote:
Hi All

Re - My previous post.... Have been doing some Googling etc and found the 'Relationships Window' 
for setting Relationships.

I can get the Window up, select my Tables but it _DOES NOT_ draw any connecting lines or set any 

Is this another "Gotcha" of using MySQL and Base together? As it does _NOT_ seem to work at all!!

I'm using PCLinuxOS 2012, LO Base and MySQL 5.1.55

Pretoria RSA.

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