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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>CREATE POLICY</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="sql-createopfamily.html" title="CREATE OPERATOR FAMILY" /><link rel="next" href="sql-createprocedure.html" title="CREATE PROCEDURE" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">CREATE POLICY</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-createopfamily.html" title="CREATE OPERATOR FAMILY">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="sql-createprocedure.html" title="CREATE PROCEDURE">Next</a></td></tr></table><hr></hr></div><div class="refentry" id="SQL-CREATEPOLICY"><div class="titlepage"></div><a id="id-1.9.3.75.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">CREATE POLICY</span></h2><p>CREATE POLICY — define a new row level security policy for a table</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">
CREATE POLICY <em class="replaceable"><code>name</code></em> ON <em class="replaceable"><code>table_name</code></em>
[ AS { PERMISSIVE | RESTRICTIVE } ]
[ FOR { ALL | SELECT | INSERT | UPDATE | DELETE } ]
[ TO { <em class="replaceable"><code>role_name</code></em> | PUBLIC | CURRENT_USER | SESSION_USER } [, ...] ]
[ USING ( <em class="replaceable"><code>using_expression</code></em> ) ]
[ WITH CHECK ( <em class="replaceable"><code>check_expression</code></em> ) ]
</pre></div><div class="refsect1" id="id-1.9.3.75.5"><h2>Description</h2><p>
The <code class="command">CREATE POLICY</code> command defines a new row-level
security policy for a table. Note that row-level security must be
enabled on the table (using <code class="command">ALTER TABLE ... ENABLE ROW LEVEL
SECURITY</code>) in order for created policies to be applied.
</p><p>
A policy grants the permission to select, insert, update, or delete rows
that match the relevant policy expression. Existing table rows are
checked against the expression specified in <code class="literal">USING</code>,
while new rows that would be created via <code class="literal">INSERT</code>
or <code class="literal">UPDATE</code> are checked against the expression specified
in <code class="literal">WITH CHECK</code>. When a <code class="literal">USING</code>
expression returns true for a given row then that row is visible to the
user, while if false or null is returned then the row is not visible.
When a <code class="literal">WITH CHECK</code> expression returns true for a row
then that row is inserted or updated, while if false or null is returned
then an error occurs.
</p><p>
For <code class="command">INSERT</code> and <code class="command">UPDATE</code> statements,
<code class="literal">WITH CHECK</code> expressions are enforced after
<code class="literal">BEFORE</code> triggers are fired, and before any actual data
modifications are made. Thus a <code class="literal">BEFORE ROW</code> trigger may
modify the data to be inserted, affecting the result of the security
policy check. <code class="literal">WITH CHECK</code> expressions are enforced
before any other constraints.
</p><p>
Policy names are per-table. Therefore, one policy name can be used for many
different tables and have a definition for each table which is appropriate to
that table.
</p><p>
Policies can be applied for specific commands or for specific roles. The
default for newly created policies is that they apply for all commands and
roles, unless otherwise specified. Multiple policies may apply to a single
command; see below for more details.
<a class="xref" href="sql-createpolicy.html#SQL-CREATEPOLICY-SUMMARY" title="Table 240. Policies Applied by Command Type">Table 240</a> summarizes how the different types
of policy apply to specific commands.
</p><p>
For policies that can have both <code class="literal">USING</code>
and <code class="literal">WITH CHECK</code> expressions (<code class="literal">ALL</code>
and <code class="literal">UPDATE</code>), if no <code class="literal">WITH CHECK</code>
expression is defined, then the <code class="literal">USING</code> expression will be
used both to determine which rows are visible (normal
<code class="literal">USING</code> case) and which new rows will be allowed to be
added (<code class="literal">WITH CHECK</code> case).
</p><p>
If row-level security is enabled for a table, but no applicable policies
exist, a <span class="quote">“<span class="quote">default deny</span>”</span> policy is assumed, so that no rows will
be visible or updatable.
</p></div><div class="refsect1" id="id-1.9.3.75.6"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="replaceable"><code>name</code></em></span></dt><dd><p>
The name of the policy to be created. This must be distinct from the
name of any other policy for the table.
</p></dd><dt><span class="term"><em class="replaceable"><code>table_name</code></em></span></dt><dd><p>
The name (optionally schema-qualified) of the table the
policy applies to.
</p></dd><dt><span class="term"><code class="literal">PERMISSIVE</code></span></dt><dd><p>
Specify that the policy is to be created as a permissive policy.
All permissive policies which are applicable to a given query will
be combined together using the Boolean <span class="quote">“<span class="quote">OR</span>”</span> operator. By creating
permissive policies, administrators can add to the set of records
which can be accessed. Policies are permissive by default.
</p></dd><dt><span class="term"><code class="literal">RESTRICTIVE</code></span></dt><dd><p>
Specify that the policy is to be created as a restrictive policy.
All restrictive policies which are applicable to a given query will
be combined together using the Boolean <span class="quote">“<span class="quote">AND</span>”</span> operator. By creating
restrictive policies, administrators can reduce the set of records
which can be accessed as all restrictive policies must be passed for
each record.
</p><p>
Note that there needs to be at least one permissive policy to grant
access to records before restrictive policies can be usefully used to
reduce that access. If only restrictive policies exist, then no records
will be accessible. When a mix of permissive and restrictive policies
are present, a record is only accessible if at least one of the
permissive policies passes, in addition to all the restrictive
policies.
</p></dd><dt><span class="term"><em class="replaceable"><code>command</code></em></span></dt><dd><p>
The command to which the policy applies. Valid options are
<code class="command">ALL</code>, <code class="command">SELECT</code>,
<code class="command">INSERT</code>, <code class="command">UPDATE</code>,
and <code class="command">DELETE</code>.
<code class="command">ALL</code> is the default.
See below for specifics regarding how these are applied.
</p></dd><dt><span class="term"><em class="replaceable"><code>role_name</code></em></span></dt><dd><p>
The role(s) to which the policy is to be applied. The default is
<code class="literal">PUBLIC</code>, which will apply the policy to all roles.
</p></dd><dt><span class="term"><em class="replaceable"><code>using_expression</code></em></span></dt><dd><p>
Any <acronym class="acronym">SQL</acronym> conditional expression (returning
<code class="type">boolean</code>). The conditional expression cannot contain
any aggregate or window functions. This expression will be added
to queries that refer to the table if row level security is enabled.
Rows for which the expression returns true will be visible. Any
rows for which the expression returns false or null will not be
visible to the user (in a <code class="command">SELECT</code>), and will not be
available for modification (in an <code class="command">UPDATE</code>
or <code class="command">DELETE</code>). Such rows are silently suppressed; no error
is reported.
</p></dd><dt><span class="term"><em class="replaceable"><code>check_expression</code></em></span></dt><dd><p>
Any <acronym class="acronym">SQL</acronym> conditional expression (returning
<code class="type">boolean</code>). The conditional expression cannot contain
any aggregate or window functions. This expression will be used in
<code class="command">INSERT</code> and <code class="command">UPDATE</code> queries against
the table if row level security is enabled. Only rows for which the
expression evaluates to true will be allowed. An error will be thrown
if the expression evaluates to false or null for any of the records
inserted or any of the records that result from the update. Note that
the <em class="replaceable"><code>check_expression</code></em> is
evaluated against the proposed new contents of the row, not the
original contents.
</p></dd></dl></div><div class="refsect2" id="id-1.9.3.75.6.3"><h3>Per-Command Policies</h3><div class="variablelist"><dl class="variablelist"><dt id="SQL-CREATEPOLICY-ALL"><span class="term"><code class="literal">ALL</code></span></dt><dd><p>
Using <code class="literal">ALL</code> for a policy means that it will apply
to all commands, regardless of the type of command. If an
<code class="literal">ALL</code> policy exists and more specific policies
exist, then both the <code class="literal">ALL</code> policy and the more
specific policy (or policies) will be applied.
Additionally, <code class="literal">ALL</code> policies will be applied to
both the selection side of a query and the modification side, using
the <code class="literal">USING</code> expression for both cases if only
a <code class="literal">USING</code> expression has been defined.
</p><p>
As an example, if an <code class="literal">UPDATE</code> is issued, then the
<code class="literal">ALL</code> policy will be applicable both to what the
<code class="literal">UPDATE</code> will be able to select as rows to be
updated (applying the <code class="literal">USING</code> expression),
and to the resulting updated rows, to check if they are permitted
to be added to the table (applying the <code class="literal">WITH CHECK</code>
expression, if defined, and the <code class="literal">USING</code> expression
otherwise). If an <code class="command">INSERT</code>
or <code class="command">UPDATE</code> command attempts to add rows to the
table that do not pass the <code class="literal">ALL</code>
policy's <code class="literal">WITH CHECK</code> expression, the entire
command will be aborted.
</p></dd><dt id="SQL-CREATEPOLICY-SELECT"><span class="term"><code class="literal">SELECT</code></span></dt><dd><p>
Using <code class="literal">SELECT</code> for a policy means that it will apply
to <code class="literal">SELECT</code> queries and whenever
<code class="literal">SELECT</code> permissions are required on the relation the
policy is defined for. The result is that only those records from the
relation that pass the <code class="literal">SELECT</code> policy will be
returned during a <code class="literal">SELECT</code> query, and that queries
that require <code class="literal">SELECT</code> permissions, such as
<code class="literal">UPDATE</code>, will also only see those records
that are allowed by the <code class="literal">SELECT</code> policy.
A <code class="literal">SELECT</code> policy cannot have a <code class="literal">WITH
CHECK</code> expression, as it only applies in cases where
records are being retrieved from the relation.
</p></dd><dt id="SQL-CREATEPOLICY-INSERT"><span class="term"><code class="literal">INSERT</code></span></dt><dd><p>
Using <code class="literal">INSERT</code> for a policy means that it will apply
to <code class="literal">INSERT</code> commands. Rows being inserted that do
not pass this policy will result in a policy violation error, and the
entire <code class="literal">INSERT</code> command will be aborted.
An <code class="literal">INSERT</code> policy cannot have
a <code class="literal">USING</code> expression, as it only applies in cases
where records are being added to the relation.
</p><p>
Note that <code class="literal">INSERT</code> with <code class="literal">ON CONFLICT DO
UPDATE</code> checks <code class="literal">INSERT</code> policies'
<code class="literal">WITH CHECK</code> expressions only for rows appended
to the relation by the <code class="literal">INSERT</code> path.
</p></dd><dt id="SQL-CREATEPOLICY-UPDATE"><span class="term"><code class="literal">UPDATE</code></span></dt><dd><p>
Using <code class="literal">UPDATE</code> for a policy means that it will apply
to <code class="literal">UPDATE</code>, <code class="literal">SELECT FOR UPDATE</code>
and <code class="literal">SELECT FOR SHARE</code> commands, as well as
auxiliary <code class="literal">ON CONFLICT DO UPDATE</code> clauses of
<code class="literal">INSERT</code> commands. Since <code class="literal">UPDATE</code>
involves pulling an existing record and replacing it with a new
modified record, <code class="literal">UPDATE</code>
policies accept both a <code class="literal">USING</code> expression and
a <code class="literal">WITH CHECK</code> expression.
The <code class="literal">USING</code> expression determines which records
the <code class="literal">UPDATE</code> command will see to operate against,
while the <code class="literal">WITH CHECK</code> expression defines which
modified rows are allowed to be stored back into the relation.
</p><p>
Any rows whose updated values do not pass the
<code class="literal">WITH CHECK</code> expression will cause an error, and the
entire command will be aborted. If only a <code class="literal">USING</code>
clause is specified, then that clause will be used for both
<code class="literal">USING</code> and <code class="literal">WITH CHECK</code> cases.
</p><p>
Typically an <code class="literal">UPDATE</code> command also needs to read
data from columns in the relation being updated (e.g., in a
<code class="literal">WHERE</code> clause or a <code class="literal">RETURNING</code>
clause, or in an expression on the right hand side of the
<code class="literal">SET</code> clause). In this case,
<code class="literal">SELECT</code> rights are also required on the relation
being updated, and the appropriate <code class="literal">SELECT</code> or
<code class="literal">ALL</code> policies will be applied in addition to
the <code class="literal">UPDATE</code> policies. Thus the user must have
access to the row(s) being updated through a <code class="literal">SELECT</code>
or <code class="literal">ALL</code> policy in addition to being granted
permission to update the row(s) via an <code class="literal">UPDATE</code>
or <code class="literal">ALL</code> policy.
</p><p>
When an <code class="literal">INSERT</code> command has an auxiliary
<code class="literal">ON CONFLICT DO UPDATE</code> clause, if the
<code class="literal">UPDATE</code> path is taken, the row to be updated is
first checked against the <code class="literal">USING</code> expressions of
any <code class="literal">UPDATE</code> policies, and then the new updated row
is checked against the <code class="literal">WITH CHECK</code> expressions.
Note, however, that unlike a standalone <code class="literal">UPDATE</code>
command, if the existing row does not pass the
<code class="literal">USING</code> expressions, an error will be thrown (the
<code class="literal">UPDATE</code> path will <span class="emphasis"><em>never</em></span> be silently
avoided).
</p></dd><dt id="SQL-CREATEPOLICY-DELETE"><span class="term"><code class="literal">DELETE</code></span></dt><dd><p>
Using <code class="literal">DELETE</code> for a policy means that it will apply
to <code class="literal">DELETE</code> commands. Only rows that pass this
policy will be seen by a <code class="literal">DELETE</code> command. There can
be rows that are visible through a <code class="literal">SELECT</code> that are
not available for deletion, if they do not pass the
<code class="literal">USING</code> expression for
the <code class="literal">DELETE</code> policy.
</p><p>
In most cases a <code class="literal">DELETE</code> command also needs to read
data from columns in the relation that it is deleting from (e.g.,
in a <code class="literal">WHERE</code> clause or a
<code class="literal">RETURNING</code> clause). In this case,
<code class="literal">SELECT</code> rights are also required on the relation,
and the appropriate <code class="literal">SELECT</code> or
<code class="literal">ALL</code> policies will be applied in addition to
the <code class="literal">DELETE</code> policies. Thus the user must have
access to the row(s) being deleted through a <code class="literal">SELECT</code>
or <code class="literal">ALL</code> policy in addition to being granted
permission to delete the row(s) via a <code class="literal">DELETE</code> or
<code class="literal">ALL</code> policy.
</p><p>
A <code class="literal">DELETE</code> policy cannot have a <code class="literal">WITH
CHECK</code> expression, as it only applies in cases where
records are being deleted from the relation, so that there is no
new row to check.
</p></dd></dl></div><div class="table" id="SQL-CREATEPOLICY-SUMMARY"><p class="title"><strong>Table 240. Policies Applied by Command Type</strong></p><div class="table-contents"><table class="table" summary="Policies Applied by Command Type" border="1"><colgroup><col /><col /><col /><col class="update-using" /><col class="update-check" /><col /></colgroup><thead><tr><th rowspan="2">Command</th><th><code class="literal">SELECT/ALL policy</code></th><th><code class="literal">INSERT/ALL policy</code></th><th colspan="2"><code class="literal">UPDATE/ALL policy</code></th><th><code class="literal">DELETE/ALL policy</code></th></tr><tr><th><code class="literal">USING expression</code></th><th><code class="literal">WITH CHECK expression</code></th><th><code class="literal">USING expression</code></th><th><code class="literal">WITH CHECK expression</code></th><th><code class="literal">USING expression</code></th></tr></thead><tbody><tr><td><code class="command">SELECT</code></td><td>Existing row</td><td>—</td><td>—</td><td>—</td><td>—</td></tr><tr><td><code class="command">SELECT FOR UPDATE/SHARE</code></td><td>Existing row</td><td>—</td><td>Existing row</td><td>—</td><td>—</td></tr><tr><td><code class="command">INSERT</code></td><td>—</td><td>New row</td><td>—</td><td>—</td><td>—</td></tr><tr><td><code class="command">INSERT ... RETURNING</code></td><td>
New row <a href="#ftn.RLS-SELECT-PRIV" class="footnote"><sup class="footnote" id="RLS-SELECT-PRIV">[a]</sup></a>
</td><td>New row</td><td>—</td><td>—</td><td>—</td></tr><tr><td><code class="command">UPDATE</code></td><td>
Existing & new rows <a href="sql-createpolicy.html#ftn.RLS-SELECT-PRIV" class="footnoteref"><sup class="footnoteref">[a]</sup></a>
</td><td>—</td><td>Existing row</td><td>New row</td><td>—</td></tr><tr><td><code class="command">DELETE</code></td><td>
Existing row <a href="sql-createpolicy.html#ftn.RLS-SELECT-PRIV" class="footnoteref"><sup class="footnoteref">[a]</sup></a>
</td><td>—</td><td>—</td><td>—</td><td>Existing row</td></tr><tr><td><code class="command">ON CONFLICT DO UPDATE</code></td><td>Existing & new rows</td><td>—</td><td>Existing row</td><td>New row</td><td>—</td></tr></tbody><tbody class="footnotes"><tr><td colspan="6"><div id="ftn.RLS-SELECT-PRIV" class="footnote"><p><a href="#RLS-SELECT-PRIV" class="para"><sup class="para">[a] </sup></a>
If read access is required to the existing or new row (for example,
a <code class="literal">WHERE</code> or <code class="literal">RETURNING</code> clause
that refers to columns from the relation).
</p></div></td></tr></tbody></table></div></div><br class="table-break" /></div><div class="refsect2" id="id-1.9.3.75.6.4"><h3>Application of Multiple Policies</h3><p>
When multiple policies of different command types apply to the same command
(for example, <code class="literal">SELECT</code> and <code class="literal">UPDATE</code>
policies applied to an <code class="literal">UPDATE</code> command), then the user
must have both types of permissions (for example, permission to select rows
from the relation as well as permission to update them). Thus the
expressions for one type of policy are combined with the expressions for
the other type of policy using the <code class="literal">AND</code> operator.
</p><p>
When multiple policies of the same command type apply to the same command,
then there must be at least one <code class="literal">PERMISSIVE</code> policy
granting access to the relation, and all of the
<code class="literal">RESTRICTIVE</code> policies must pass. Thus all the
<code class="literal">PERMISSIVE</code> policy expressions are combined using
<code class="literal">OR</code>, all the <code class="literal">RESTRICTIVE</code> policy
expressions are combined using <code class="literal">AND</code>, and the results are
combined using <code class="literal">AND</code>. If there are no
<code class="literal">PERMISSIVE</code> policies, then access is denied.
</p><p>
Note that, for the purposes of combining multiple policies,
<code class="literal">ALL</code> policies are treated as having the same type as
whichever other type of policy is being applied.
</p><p>
For example, in an <code class="literal">UPDATE</code> command requiring both
<code class="literal">SELECT</code> and <code class="literal">UPDATE</code> permissions, if
there are multiple applicable policies of each type, they will be combined
as follows:
</p><pre class="programlisting">
<em class="replaceable"><code>expression</code></em> from RESTRICTIVE SELECT/ALL policy 1
AND
<em class="replaceable"><code>expression</code></em> from RESTRICTIVE SELECT/ALL policy 2
AND
...
AND
(
<em class="replaceable"><code>expression</code></em> from PERMISSIVE SELECT/ALL policy 1
OR
<em class="replaceable"><code>expression</code></em> from PERMISSIVE SELECT/ALL policy 2
OR
...
)
AND
<em class="replaceable"><code>expression</code></em> from RESTRICTIVE UPDATE/ALL policy 1
AND
<em class="replaceable"><code>expression</code></em> from RESTRICTIVE UPDATE/ALL policy 2
AND
...
AND
(
<em class="replaceable"><code>expression</code></em> from PERMISSIVE UPDATE/ALL policy 1
OR
<em class="replaceable"><code>expression</code></em> from PERMISSIVE UPDATE/ALL policy 2
OR
...
)
</pre></div></div><div class="refsect1" id="id-1.9.3.75.7"><h2>Notes</h2><p>
You must be the owner of a table to create or change policies for it.
</p><p>
While policies will be applied for explicit queries against tables
in the database, they are not applied when the system is performing internal
referential integrity checks or validating constraints. This means there are
indirect ways to determine that a given value exists. An example of this is
attempting to insert a duplicate value into a column that is a primary key
or has a unique constraint. If the insert fails then the user can infer that
the value already exists. (This example assumes that the user is permitted by
policy to insert records which they are not allowed to see.) Another example
is where a user is allowed to insert into a table which references another,
otherwise hidden table. Existence can be determined by the user inserting
values into the referencing table, where success would indicate that the
value exists in the referenced table. These issues can be addressed by
carefully crafting policies to prevent users from being able to insert,
delete, or update records at all which might possibly indicate a value they
are not otherwise able to see, or by using generated values (e.g., surrogate
keys) instead of keys with external meanings.
</p><p>
Generally, the system will enforce filter conditions imposed using
security policies prior to qualifications that appear in user queries,
in order to prevent inadvertent exposure of the protected data to
user-defined functions which might not be trustworthy. However,
functions and operators marked by the system (or the system
administrator) as <code class="literal">LEAKPROOF</code> may be evaluated before
policy expressions, as they are assumed to be trustworthy.
</p><p>
Since policy expressions
are added to the user's query directly, they will be run with the rights of
the user running the overall query. Therefore, users who are using a given
policy must be able to access any tables or functions referenced in the
expression or they will simply receive a permission denied error when
attempting to query the table that has row-level security enabled.
This does not change how views
work, however. As with normal queries and views, permission checks and
policies for the tables which are referenced by a view will use the view
owner's rights and any policies which apply to the view owner.
</p><p>
Additional discussion and practical examples can be found
in <a class="xref" href="ddl-rowsecurity.html" title="5.7. Row Security Policies">Section 5.7</a>.
</p></div><div class="refsect1" id="id-1.9.3.75.8"><h2>Compatibility</h2><p>
<code class="command">CREATE POLICY</code> is a <span class="productname">PostgreSQL</span>
extension.
</p></div><div class="refsect1" id="id-1.9.3.75.9"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-alterpolicy.html" title="ALTER POLICY"><span class="refentrytitle">ALTER POLICY</span></a>, <a class="xref" href="sql-droppolicy.html" title="DROP POLICY"><span class="refentrytitle">DROP POLICY</span></a>, <a class="xref" href="sql-altertable.html" title="ALTER TABLE"><span class="refentrytitle">ALTER TABLE</span></a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sql-createopfamily.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-createprocedure.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">CREATE OPERATOR FAMILY </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> CREATE PROCEDURE</td></tr></table></div></body></html>
