So I can see why someone might think they need to know the pseudokey, but they are incorrect. Seems to me that there is no need to EVER deal with the pseudokeys. Below we’ll examine the three different methods and explain the pros and cons of each in turn. MySQL provides a number of useful statements when it is necessary to INSERT rows after determining whether that row is, in fact, new or already exists. Filter out those rows from df0 and df2, whose corresponding combinedcolumn does not. How to INSERT If Row Does Not Exist (UPSERT) in MySQL. combinedcolumn, and save this into a list combinedcolumnlist. (select house_id from houses where address = new.address) There are two ways: if the data from database is not big, read the data from database into the dataframe, and combine the two columns (Col1 and Col2) to create a new column, i.e. Select (select name_id from names where name = new.name), Insert or ignore into houses (address) select new.address where new.address is not null Insert or ignore into names (name) values (new.name) Select raise(ABORT, 'Name cannot be NULL') where new.name is null Where (peasants.name_id is null or peasants.name_id = names.name_id)Īnd (peasants.house_id is null or peasants.house_id = houses.house_id) Ĭreate trigger ins_person instead of insert into persons It is actually not needed for anything at all.Īddress text not null collate nocase unique It also does not really matter what some excrement-head thinks "after the fact" - they can either accept the answer "I don't know" (which by the way is an incorrect answer - the correct answer would be "that information was not recorded").Īnd going back to the post to which you replied, it only appears to the uneducated that there is a need to know the pseudokey for the row. Playing with pseudokeys will not be helpful in this regard. Unless the inserted record contains a timestamp of when it was inserted, there is no way to tell when the record was inserted. Note that if the ID field is set to autoincrement, then the IDs. Well, that is a design flaw (failure to store needed information) and has nothing whatsoever to do with the question asked. You can do this with a unique constraint & insert or ignore.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |