postgresql - Create unique identifier for more persons that are the same (SQL) -

-



i have 2 tables:

|-------------|   |-------------| | person      |   | alias       | |-------------|   |-------------| | person_id   |   | person_id_1 |    | person_name |   | person_id_2 | |-------------|   |-------------|

the alias table tells me if 2 persons in fact same person. if case, want have unique id these persons.

e. g.: |-------------------------| | person | |-----------|-------------| | person_id | person_name | |-----------|-------------| | 1 | michail | |-----------|-------------| | 2 | michail | |-----------|-------------| | 3 | petja | |-----------|-------------|

|---------------------------| | alias | |-------------|-------------| | person_id_1 | person_id_2 | |-------------|-------------| | 1 | 2 | |-------------|-------------|

now want create view, query, you name it, lists me person_ids , unique identifier these ids.

|-----------------------| | unique id view        | |-----------------------| | unique_id | person_id | |-----------------------| | xe3rf     | 1         | | xe3rf     | 2         | | y23ij     | 3         | |-----------------------|

can me unique id view? totally clueless atm :-(

thanks inb4,

michail

i think have value can use uniqe id. have force person_id_1 unique on same person. make sure don't have tree-like references:

1 -> 2 2 -> 3 2 -> 4

these tree-like connections difficult handle in sql.

lets rename person_id_1 original_id , person_id_2 secondary_id. if find new connection, "5 duplicate 3", query table:

  • is 3 exists on original_id column? if yes, insert new connection.
  • is 3 exists on secondary_id column? if yes, query row's original_id, , insert new connection that.

this way can avoid chains, , query want simple as

select * alias

as @a_horse_with_no_name suggested, can simply use query recursive with statement too:

with recursive conn(person_id_1, person_id_2) (     select person_id_1, person_id_2 alias   union     select alias.person_id_1, conn.person_id_2     alias, conn     alias.person_id_2 = conn.person_id_1 ), leaf_nodes (   select distinct person_id_2 alias ) select *  conn conn.person_id_1 not in (select person_id_2 leaf_nodes) order person_id_1;




wiki

Comments

Post a Comment

Popular posts from this blog

elasticsearch - what is the equivalent data type for geo_point in hibernate search? -

-
i using elastic search hibernate search.i want make 1 property data type geo_point ,so can draw tile map using kibana.is there equivalent data type in hibernate search geo_point in elastic search? you can use spatial feature of hibernate search: import org.hibernate.search.annotations.*; @entity @indexed @spatial public class hotel { @latitude double latitude @longitude double longitude // ... } you end geo_point field named location in document. for more information: https://docs.jboss.org/hibernate/stable/search/reference/en-us/html_single/#spatial wiki
Read more

Jenkins: find build number for git commit -

-
each commit git repo triggers build of jenkins pipeline. i want retrieve buildnumber of old build commit hash. how can that? i know information exists because can find in ui. some background why want this: when tags commit want create release (by tagging docker image). each build push image containing build number. want find out build number corresponds commit can find image want release. if understand question correctly, first need create git hook trigger new build. part covered in answer how react new tags in git hooks? ', though if using github, bitbucket or gitlab, there may other ways of going it. then when build initiated, there build number provided variable ' build_number ' ,in jenkins. if want include git tag name, can use in script, there seems fews ways: git parameter plugin git tag message plugin typically these plugins create environment variable can consumed scripts. not providing more concrete examples, since not aware of exact ...
Read more

firebase - How to wait value in Ionic 2 -

-
i'm trying wait value may change after execute "this.bookmarlist.take(1).subscribe(..." my problem when run application, execute second if statement "if(found==false)" before execute subscribe. this code may found thing wrong or need add additions solve problem. let loader = this.loadingctrl.create({ content: "", }); let found=false; loader.present().then(()=>{ this.bookmarklist.take(1).subscribe(data=>{ data.foreach(b=>{ if(b.nid==this.appservice.id && b.url==url){ let alert = this.alertctrl.create({ title: 'already bookmarked', subtitle: 'this note image bookmarked', buttons: ['ok'] }); alert.present(); found=true; } }) }) }).then(()=>{ if(found==false){ this.afd.list('/bookmark/').push({ uemail: th...
Read more