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What if there is no primary key in table?
Every table can have (but does not have to have) a primary key. The column or columns defined as the primary key ensure uniqueness in the table; no two rows can have the same key. The primary key of one table may also help to identify records in other tables, and be part of the second table’s primary key.
Can an entity not have a primary key?
EF does not require a primary key on the database. If it did, you couldn’t bind entities to views. You can modify the SSDL (and the CSDL) to specify a unique field as your primary key.
Which is the primary key for each table?
The primary key for each of the tables is a composite key. I know there is a different number of rows in each one and I need to find out the differences. Typically, in the “normal” primary key set-up, I would just look for primary key values NOT IN the list of primary keys from the other table.
How can I compare two tables without matches?
After the wizard builds your query, you can modify the query’s design to add or remove fields, or to add joins between the two tables (to indicate fields whose values should match). You can also create your own query to find unmatched records, without using the wizard.
Can a composite primary key be used as a primary key?
I know there is a different number of rows in each one and I need to find out the differences. Typically, in the “normal” primary key set-up, I would just look for primary key values NOT IN the list of primary keys from the other table. But I don’t know how to do this with a composite primary key (or even if it’s possible).
How to find duplicate data in two tables?
You can often approach the problem of overlapping, redundant, or conflicting information by looking for duplicate data in two or more tables. For more information about union queries, or about finding, hiding, or eliminating duplicate data, click the links in the See Also section.