Schema search path

posted Apr 28, 2017, 4:23 PM by Sachchida Ojha
Search path parameter specifies the order in which schemas are searched when an object is referenced by a simple name with no schema component.

When there are objects of identical names in different schemas, the one found first in the search path is used. The system catalog schema, pg_catalog, is always searched, whether it is mentioned in the path or not. When objects are created without specifying a particular target schema, they will be placed in the first schema listed in the search path. The current effective value of the search path can be examined via the SQL function current_schemas(). current_schemas() shows how the requests appearing in search_path were resolved

Default is $user,public

SHOW search_path; 

In the default setup this returns: 

search_path 
-------------- 
 "$user",public

The first element specifies that a schema with the same name as the current user is to be searched. If no such schema exists, the entry is ignored. The second element refers to the public schema that we have seen already.

The first schema in the search path that exists is the default location for creating new objects. That is the reason that by default objects are created in the public schema. When objects are referenced in any other context without schema qualification (table modification, data modification, or query commands) the search path is traversed until a matching object is found. Therefore, in the default configuration, any unqualified access again can only refer to the public schema.

To put our new schema in the path, we use

SET search_path TO myschema,public;
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