Return to Answer

PostgreSQL can address your needs via it's "Partial Index" feature. In practice this is accomplished by adding a where clause to the create index statement.

Sample:

CREATE INDEX my_partial_ix ON my_sample_table (my_sample_field) WHERE NOT (my_sample_field = 'duplicates ok'); 

Take a look here: http://www.postgresql.org/docs/current/interactive/indexes-partial.html

Pay particular attention to the section Example 11-3. Setting up a Partial Unique Index. It gives an example that lines up well with your stated objective.

PostgreSQL can address your needs via it's "Partial Index" feature. In practice this is accomplished by adding a where clause to the create index statement.

Sample:

CREATE INDEX my_partial_ix ON my_sample_table (my_sample_field) WHERE (my_sample_field = 'rows to index'); 

Take a look here: http://www.postgresql.org/docs/current/interactive/indexes-partial.html

Pay particular attention to the section Example 11-3. Setting up a Partial Unique Index. It gives an example that lines up well with your stated objective.

CREATE UNIQUE INDEX my_partial_ix ON my_sample_table (my_sample_field) WHERE NOT (my_sample_field = 'duplicates ok'); 

PostgresSQL can address your needs via it's "Partial Index" feature. In practice this is accomplished by adding a where clause to the create index statement.

Sample:

CREATE INDEX my_partial_ix ON my_sample_table (my_sample_field) WHERE NOT (my_sample_field = 'duplicates ok'); 

Take a look here: http://www.postgresql.org/docs/current/interactive/indexes-partial.html

Pay particular attention to the section Example 11-3. Setting up a Partial Unique Index. It gives an example that lines up well with your stated objective.

PostgreSQL can address your needs via it's "Partial Index" feature. In practice this is accomplished by adding a where clause to the create index statement.

Sample:

CREATE INDEX my_partial_ix ON my_sample_table (my_sample_field) WHERE NOT (my_sample_field = 'duplicates ok'); 

Take a look here: http://www.postgresql.org/docs/current/interactive/indexes-partial.html

Pay particular attention to the section Example 11-3. Setting up a Partial Unique Index. It gives an example that lines up well with your stated objective.

PostgresSQL can address your needs via it's "Partial Index" feature.

Take a look here: http://www.postgresql.org/docs/current/interactive/indexes-partial.html

Pay particular attention to the section Example 11-3. Setting up a Partial Unique Index. It gives an example that lines up well with your stated objective.

PostgresSQL can address your needs via it's "Partial Index" feature. In practice this is accomplished by adding a where clause to the create index statement.

Sample:

CREATE INDEX my_partial_ix ON my_sample_table (my_sample_field) WHERE NOT (my_sample_field = 'duplicates ok'); 

Take a look here: http://www.postgresql.org/docs/current/interactive/indexes-partial.html

Pay particular attention to the section Example 11-3. Setting up a Partial Unique Index. It gives an example that lines up well with your stated objective.