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plurals

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6562121
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0
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2011-07-03T09:36:20.887
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2011-07-03T09:36:20.887
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<blockquote> Originally I have 3 tables. </blockquote> Ok. <blockquote> Table B references Table A. So now Table B has two primary keys. One used as the original primary key and the other one to enforce its relationship with Tabe A. </blockquote> No. Table B has one primary key and one foreign key. The foreign key might be part of the primary key, and it might not. <blockquote> Then I want Table B to have a many-to-many relationship with Table X. </blockquote> Ok. <blockquote> As I'm adding the relationship, MySQL Workbench added Table Y with both of Table B primary keys and one primary key in Table X. So Table Y now has three primary keys. </blockquote> A many-to-many relationship is typically implemented as a table that contains two foreign keys as its primary key. In your case, one foreign key is the primary key of Table B, and the other foreign key is the primary key of Table X. The primary key of Table B seems to contain two columns. The tables might look like this. <ul> <li>Table A: {a1, a2}</li> <li>Table B: {b1, a1, b2, b3}, a1 references Table A</li> <li>Table X: {x1, x2}</li> </ul> Table Y, which implements the m:n relationship, contains the keys from B and from X. <ul> <li>Table Y: {b1, a1, x1}, the two columns b1, a1 reference Table B; the column x1 references Table X</li> </ul> If you want better answers, edit your question and include the SQL DDL for your tables. Get the DDL by using <a href="http://dev.mysql.com/doc/refman/5.0/en/show-create-table.html" rel="nofollow">SHOW CREATE TABLE</a>.
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singulars
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1. This table or related slice is empty.
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1. POShould junction tables have more than one primary keys from another indentifying table?
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1. PTAnswer
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1. This table or related slice is empty.
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1. USMike Sherrill 'Cat Recall'
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1. COI've edited my post to include the diagram.
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 USDalton Tan
2. COI'll look at it when you get around to posting the SQL DDL.
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 USMike Sherrill 'Cat Recall'

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Guidance

A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.