partial-index

What are the limitations of partial indexes?

由 牧云@^-^@ 提交于 2019-12-19 07:26:32
问题 The latest version of MongoDB (v3.2) adds support for partial (filtered) indexes. You supply a filter when you create the index and that filter determines which documents will be referenced in the index and which will not. Can I use any filter expression (as long as it's a valid filter)? Or are there limitations to the filter being used? If so, what are those limitations? 回答1: Can I use any filter expression? No, partial indexes support only a subset of the operators in the filter used. The

What are the limitations of partial indexes?

由 风格不统一 提交于 2019-12-19 07:25:07
问题 The latest version of MongoDB (v3.2) adds support for partial (filtered) indexes. You supply a filter when you create the index and that filter determines which documents will be referenced in the index and which will not. Can I use any filter expression (as long as it's a valid filter)? Or are there limitations to the filter being used? If so, what are those limitations? 回答1: Can I use any filter expression? No, partial indexes support only a subset of the operators in the filter used. The

What are the limitations of partial indexes?

由 只愿长相守 提交于 2019-12-19 07:25:00
问题 The latest version of MongoDB (v3.2) adds support for partial (filtered) indexes. You supply a filter when you create the index and that filter determines which documents will be referenced in the index and which will not. Can I use any filter expression (as long as it's a valid filter)? Or are there limitations to the filter being used? If so, what are those limitations? 回答1: Can I use any filter expression? No, partial indexes support only a subset of the operators in the filter used. The

Partial Index not used in ON CONFLICT clause while performing an upsert in Postgresql

由 余生长醉 提交于 2019-12-18 08:25:26
问题 I have the following Entity Attribute value table : CREATE TABLE key_value_pair ( id serial NOT NULL PRIMARY KEY, key varchar(255) NOT NULL, value varchar(255), is_active boolean ); CREATE UNIQUE INDEX key_value_pair_key_if_is_active_true_unique ON key_value_pair (key) WHERE is_active = true; Sample entries in this table are : id | key | value | is_active ----+-------------+-------+----------- 1 | temperature | 2 | f 2 | temperature | 12 | f 3 | temperature | 15 | f 4 | temperature | 19 | f 5

'one-to-many' relation integrity issue for time ranges

由 ╄→гoц情女王★ 提交于 2019-12-13 20:04:19
问题 Suppose I have table like: CREATE TABLE foo ( id SERIAL PRIMARY KEY , barid integer NOT NULL REFERENCES bar(id) , bazid integer NOT NULL REFERENCES baz(id) , startdate timestamp(0) NOT NULL , enddate timestamp(0) NOT NULL ); The purpose for that table is to provide a pseudo 'one-to-many' relation between tables bar and baz, but the relation can change through time: SELECT * FROM bar JOIN foo on TRUE AND foo.barid = bar.id AND now() BETWEEN foo.startdate AND foo.enddate JOIN baz on baz.id =

Workaround in mysql for partial Index or filtered Index?

由 假如想象 提交于 2019-12-01 14:41:01
问题 I am using mysql db. I know postgresql and SQL server supports partial Indexing. In my case I want to do something like this: CREATE UNIQUE INDEX myIndex ON myTable (myColumn) where myColumn <> 'myText' I want to create a unique constraint but it should allow duplicates if it is a particular text. I couldn't find a direct way to do this in mysql. But, is there a workaround to achieve it? 回答1: I suppose there is only one way to achieve it. You can add another column to your table, create index

What are the limitations of partial indexes?

由 半城伤御伤魂 提交于 2019-12-01 05:09:56
The latest version of MongoDB (v3.2) adds support for partial (filtered) indexes . You supply a filter when you create the index and that filter determines which documents will be referenced in the index and which will not. Can I use any filter expression (as long as it's a valid filter)? Or are there limitations to the filter being used? If so, what are those limitations? Can I use any filter expression? No, partial indexes support only a subset of the operators in the filter used. The only supported operators are: $AND (only at the top level), $EQ , $LT , $LTE , $GT , $GTE , $EXISTS and the

Partial Index not used in ON CONFLICT clause while performing an upsert in Postgresql

由 爷，独闯天下 提交于 2019-11-29 14:19:55
I have the following Entity Attribute value table : CREATE TABLE key_value_pair ( id serial NOT NULL PRIMARY KEY, key varchar(255) NOT NULL, value varchar(255), is_active boolean ); CREATE UNIQUE INDEX key_value_pair_key_if_is_active_true_unique ON key_value_pair (key) WHERE is_active = true; Sample entries in this table are : id | key | value | is_active ----+-------------+-------+----------- 1 | temperature | 2 | f 2 | temperature | 12 | f 3 | temperature | 15 | f 4 | temperature | 19 | f 5 | temperature | 23 | t (5 rows) Thus, at any point in time, for any given key, only 1 true is_active
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