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  1. How add unique key to existing table (with non uniques rows) ... I want to add complex unique key to existing table. Key contains from 4 fields (user_id, ...
    stackoverflow.com/questions/15255304/​how-add-unique-key... - Cached

  2. Unique key - Wikipedia, the free encyclopedia

    ... each data entity usually becomes a database table, unique keys ... add such a constraint to an existing table ... unique key automatically generates a non ...
    en.wikipedia.org/wiki/Unique_key - Cached
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  3. ... COLLATE latin1_general_ci, UNIQUE KEY ID (ID) ); ... Create a new table from two existing tables. 0. How add unique key to existing table (with non uniques rows) 0.
    stackoverflow.com/...on-unique-ke y-when-​creating-a-table - Cached
  4. [PDF]

    Advancing the Discovery of Unique Column Combinations

    Adobe PDF
    unique to a key, because uniques can appear by ... rows of a table. A recursive unique discovery algorithm ... -candidates is to add non-contained 1-non-uniques
    www.hpi.uni-potsdam.de/.../unique_​discovery_techReport.pdf
  5. Multiple column unique key allows multiple rows? ... table test add constraint test_uk unique ... only if no two rows in a table have the same non-null values ...
    bugs.mysql.com/bug.php?id=25544 - Cached
  6. The UNIQUE constraint uniquely identifies each record in a database table. The UNIQUE and PRIMARY KEY constraints both provide a ... ALTER TABLE Persons ADD UNIQUE ...
    www.w3schools.com/sql /sql_unique.asp - Cached
  7. Entity Integrity ensures that there are no duplicate rows in a table. ... add constraints to an existing table by ... unique key constraint into an existing table ...
    mssqlcity.com/Articles/General/using_​constraints.htm - Cached
  8. Unique Key creates a non-clustered index on ... primary key is u nique identifiying rows in s ... I want Add Unique key constraint on my existing table which ...
    blog.sqlauthority.com/2007/​...key...unique-key-constraints - Cached
  9. All colu mns included in a primary key must contain non null data and be unique. ... ALTER TABLE ADD UNIQUE or PRIMARY KEY ... in all existing rows in the table ...
    db.apache.org/derby/docs/10.8/ref/​rrefsqlj81859.html - Cached
  10. Add a unique table column in MySQL to ensure you do not have any duplicates, ... and make sure that it\'s not a duplicate of any of the already existing columns.
    php.about.com/od/mysqlcommands/g/add_​unique.htm - Cached