When you run an ordinary query, a malicious user able to create objects in a schema of your search path can take control and execute arbitrary SQL functions as though you executed them. Due to the prevalence of unqualified names in queries and their use in PostgreSQL internals, adding a schema to search_path effectively trusts all users having CREATE privilege on that schema. It also opens up the potential for users to change the behavior of other users' queries, maliciously or accidentally. The ability to create like-named objects in different schemas complicates writing a query that references precisely the same objects every time.
If there is no match in the search path, an error is reported, even if matching table names exist in other schemas in the database. The first matching table in the search path is taken to be the one wanted. The system determines which table is meant by following a search path, which is a list of schemas to look in. Therefore tables are often referred to by unqualified names, which consist of just the table name. Qualified names are tedious to write, and it's often best not to wire a particular schema name into applications anyway. Schema names beginning with pg_ are reserved for system purposes and cannot be created by users.
See Section 5.9.6 for how this can be useful. You can even omit the schema name, in which case the schema name will be the same as the user name. The syntax for that is:ĬREATE SCHEMA schema_name AUTHORIZATION user_name Often you will want to create a schema owned by someone else (since this is one of the ways to restrict the activities of your users to well-defined namespaces). See Section 5.14 for a description of the general mechanism behind this. To drop a schema including all contained objects, use: To drop a schema if it's empty (all objects in it have been dropped), use: So to create a table in the new schema, use: If you write a database name, it must be the same as the database you are connected to.
#POSTGRESQL CREATE TABLE IN SCHEMA PRO#
tableĬan be used too, but at present this is just for pro forma compliance with the SQL standard. (For brevity we will speak of tables only, but the same ideas apply to other kinds of named objects, such as types and functions.)Īctually, the even more general syntax database. This works anywhere a table name is expected, including the table modification commands and the data access commands discussed in the following chapters. To create or access objects in a schema, write a qualified name consisting of the schema name and table name separated by a dot: schema. To create a schema, use the CREATE SCHEMA command.
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