Re^3: Update XML Values using two primary keys

They could both be keys but I don't see how they could both be primary unless combined into a single primary key as jcb suggested. Do you happen to use or know of a database that supports multiple primary keys on the same table?

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Comment on Re^3: Update XML Values using two primary keys

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Re^4: Update XML Values using two primary keys by jcb (Parson) on Jan 06, 2021 at 23:31 UTC
Logically, the primary key here is a "geographic point" type, but SQL does allow a primary key to be declared as an arbitrary tuple of multiple columns in the same table. The `PRIMARY KEY` constraint must be written as a table constraint instead of a column constraint to do this. For our questioner's example, and assuming a database that does not directly support lat/long coordinates (i.e. not Postgres with PostGIS installed), there could be a table like: (untested) `CREATE TABLE tags ( lat numeric(24,20), lon numeric(24,20), name text, PRIMARY KEY(lat, lon));` [download]	[reply] [d/l] [select]

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Re^4: Update XML Values using two primary keys
by jcb (Parson) on Jan 06, 2021 at 23:31 UTC

Logically, the primary key here is a "geographic point" type, but SQL does allow a primary key to be declared as an arbitrary tuple of multiple columns in the same table. The PRIMARY KEY constraint must be written as a table constraint instead of a column constraint to do this.

For our questioner's example, and assuming a database that does not directly support lat/long coordinates (i.e. not Postgres with PostGIS installed), there could be a table like: (untested)

CREATE TABLE tags (
    lat  numeric(24,20),
    lon  numeric(24,20),
    name text,
    PRIMARY KEY(lat, lon));
[download]

[reply]
[d/l]
[select]