doc: add examples of creative use of unique expression indexes
Unique expression indexes can constrain data in creative ways, so show
two examples.
Reported-by: Tuomas Leikola
Discussion: https://postgr.es/m/156760275564.1127.12321702656456074572@wrigleys.postgresql.org
Backpatch-through: 9.4
Branch
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REL9_4_STABLE
Details
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https://git.postgresql.org/pg/commitdiff/645694731ca9526bfcb976ae7be17b9bd8de6294
Modified Files
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doc/src/sgml/indices.sgml | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)