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| -rw-r--r-- | src/man/create_index.l | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/src/man/create_index.l b/src/man/create_index.l index 586ec95867..fd69a620c1 100644 --- a/src/man/create_index.l +++ b/src/man/create_index.l @@ -1,6 +1,6 @@ .\" This is -*-nroff-*- .\" XXX standard disclaimer belongs here.... -.\" $Header: /cvsroot/pgsql/src/man/Attic/create_index.l,v 1.3 1996/12/11 00:27:14 momjian Exp $ +.\" $Header: /cvsroot/pgsql/src/man/Attic/create_index.l,v 1.4 1997/01/13 17:22:25 momjian Exp $ .TH "CREATE INDEX" SQL 11/05/95 PostgreSQL PostgreSQL .SH NAME create index \(em construct a secondary index @@ -62,6 +62,11 @@ and then comparing it to the value on the other side of the operator. Obviously, the decision to build a functional index represents a tradeoff between space (for the index) and execution time. .PP +The \fBunique\fR keyword causes the system to check for duplicate +values when the index is created (if data already exist) and each +time data is added. +Attempts to insert or update non-duplicate data will generate an error. +.PP Postgres provides btree, rtree and hash access methods for secondary indices. The btree access method is an implementation of the Lehman-Yao high-concurrency btrees. The rtree access method |