On Thu, 28 Jan 2016 19:18:06 -0500 "Keith Medcalf" <kmedcalf at dessus.com> wrote:
> > When you create a table thusly: > > create table x (x primary key, y, z); > > you are creating a rowid table with columns x, y, an z. You are also saying > that you want x to be the primary key. Therefore, you will get a table > called x containing (ROWID, X, Y, Z). This is a btree where the index is the > rowid. In order to implement you PRIMARY KEY, an index must be constructed > containing the column X and ROWID in the table where the value of X is found. > This index will be called sqlite_autoindex_x_1 because it is the first index > created automatically on table x. Close to what I was suspecting. Thanks for these points. > You could achieve the same result as follows: > > create table x (x, y, z); > create unique index pk_x_x on x(x); > > except that now you have given the index on x an explicit name and one does > not have to be manufactured for you. > I checked these indexes gets created even if I manually define similar indexes. But I don't mind. After some experiments, this seems more related to ROWID, and you seem to confirm a relation, above. -- Yannick Duch?ne
