How to prevent duplicate entries in MySQL and PHP?
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I would like to come up with a standard practice to prevent any tables from having duplicates where it matters. In most cases duplicates are a combination of variables rather than one. My primary keys are just the unique ids for each field so I cannot use them. What I have been doing is querying the table first and then if the number of rows for the combination in question is 0, making the insert. However, I have read it should be possible to set up a unique key over multiple fields to enforce uniqueness...
Answer:
You can simply create a multiple-column index on these columns and enforce uniqueness: see the MySQL...
user1260310 at Stack Overflow Mark as irrelevant Undo
Other solutions
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I need to remove similar entries in a table. e.g. if there is a table of street names with x, y coordinates, then I want to remove street names that are the same name AND within close proximity. If we define 'close proximity' to be "((x2-x1)^2 ...
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Answer:
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