<row>

<entry><structfield>attfdwoptions</structfield></entry>

<entry><type>text[]</type></entry>

<entry></entry>

<entry>

Attribute-level foreign data wrapper options, as <quote>keyword=value</> strings

</entry>

</row>

<sect1 id="infoschema-column-options">

<title><literal>column_options</literal></title>

<para>

The view <literal>column_options</literal> contains all the

options defined for foreign table columns in the current database. Only

those foreign table columns are shown that the current user has access to

(by way of being the owner or having some privilege).

</para>

<table>

<title><literal>column_options</literal> Columns</title>

<tgroup cols="3">

<thead>

<row>

<entry>Name</entry>

<entry>Data Type</entry>

<entry>Description</entry>

</row>

</thead>

<tbody>

<row>

<entry><literal>table_catalog</literal></entry>

<entry><type>sql_identifier</type></entry>

<entry>Name of the database that contains the foreign table (always the current database)</entry>

</row>

<row>

<entry><literal>table_schema</literal></entry>

<entry><type>sql_identifier</type></entry>

<entry>Name of the schema that contains the foreign table</entry>

</row>

<row>

<entry><literal>table_name</literal></entry>

<entry><type>sql_identifier</type></entry>

<entry>Name of the foreign table</entry>

</row>

<row>

<entry><literal>column_name</literal></entry>

<entry><type>sql_identifier</type></entry>

<entry>Name of the column</entry>

</row>

<row>

<entry><literal>option_name</literal></entry>

<entry><type>sql_identifier</type></entry>

<entry>Name of an option</entry>

</row>

<row>

<entry><literal>option_value</literal></entry>

<entry><type>character_data</type></entry>

<entry>Value of the option</entry>

</row>

</tbody>

</tgroup>

</table>

</sect1>

ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> OPTIONS ( [ ADD | SET | DROP ] <replaceable class="PARAMETER">option</replaceable> ['<replaceable class="PARAMETER">value</replaceable>'] [, ... ])

Change options for the foreign table or one of its columns.

if no operation is explicitly specified. Duplicate option names are not

allowed (although it's OK for a table option and a column option to have

the same name). Option names and values are also validated using the

foreign data wrapper library.

{ <replaceable class="PARAMETER">column_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [ OPTIONS ( <replaceable class="PARAMETER">option</replaceable> '<replaceable class="PARAMETER">value</replaceable>' [, ... ] ) ] [ NULL | NOT NULL ] }

Options to be associated with the new foreign table or one of its

columns.

validator function. Duplicate option names are not allowed (although

it's OK for a table option and a column option to have the same name).

<para>

For some types of relation, <literal>\d</> shows additional information

for each column: column values for sequences, indexed expression for

indexes and per-column foreign data wrapper options for foreign tables.

</para>

/* attacl, attoptions and attfdwoptions are not even present... */

/* attacl, attoptions and attfdwoptions are not present in tupledescs */

attoptions => '_null_',

attfdwoptions => '_null_'

delete $row->{attfdwoptions};

nulls[Anum_pg_attribute_attfdwoptions - 1] = true;

CREATE VIEW _pg_foreign_table_columns AS

SELECT n.nspname,

c.relname,

a.attname,

a.attfdwoptions

FROM pg_foreign_table t, pg_authid u, pg_namespace n, pg_class c,

pg_attribute a

WHERE u.oid = c.relowner

AND (pg_has_role(c.relowner, 'USAGE')

OR has_column_privilege(c.oid, a.attnum, 'SELECT, INSERT, UPDATE, REFERENCES'))

AND n.oid = c.relnamespace

AND c.oid = t.ftrelid

AND c.relkind = 'f'

AND a.attrelid = c.oid

AND a.attnum > 0;

CREATE VIEW column_options AS

SELECT CAST(current_database() AS sql_identifier) AS table_catalog,

c.nspname AS table_schema,

c.relname AS table_name,

c.attname AS column_name,

CAST((pg_options_to_table(c.attfdwoptions)).option_name AS sql_identifier) AS option_name,

CAST((pg_options_to_table(c.attfdwoptions)).option_value AS character_data) AS option_value

FROM _pg_foreign_table_columns c;

GRANT SELECT ON column_options TO PUBLIC;

static void ATExecAlterColumnGenericOptions(Relation rel, const char *colName,

List *options, LOCKMODE lockmode);

case AT_AlterColumnGenericOptions:

case AT_AlterColumnGenericOptions:

ATSimplePermissions(rel, ATT_FOREIGN_TABLE);

/* This command never recurses */

/* No command-specific prep needed */

pass = AT_PASS_MISC;

break;

case AT_AlterColumnGenericOptions: /* ALTER COLUMN OPTIONS */

ATExecAlterColumnGenericOptions(rel, cmd->name, (List *) cmd->def, lockmode);

break;

static void

ATExecAlterColumnGenericOptions(Relation rel,

const char *colName,

List *options,

LOCKMODE lockmode)

{

Relation ftrel;

Relation attrel;

ForeignServer *server;

ForeignDataWrapper *fdw;

HeapTuple tuple;

HeapTuple newtuple;

bool isnull;

Datum repl_val[Natts_pg_attribute];

bool repl_null[Natts_pg_attribute];

bool repl_repl[Natts_pg_attribute];

Datum datum;

Form_pg_foreign_table fttableform;

Form_pg_attribute atttableform;

if (options == NIL)

return;

/* First, determine FDW validator associated to the foreign table. */

ftrel = heap_open(ForeignTableRelationId, AccessShareLock);

tuple = SearchSysCache1(FOREIGNTABLEREL, rel->rd_id);

if (!HeapTupleIsValid(tuple))

ereport(ERROR,

(errcode(ERRCODE_UNDEFINED_OBJECT),

errmsg("foreign table \"%s\" does not exist",

RelationGetRelationName(rel))));

fttableform = (Form_pg_foreign_table) GETSTRUCT(tuple);

server = GetForeignServer(fttableform->ftserver);

fdw = GetForeignDataWrapper(server->fdwid);

heap_close(ftrel, AccessShareLock);

ReleaseSysCache(tuple);

attrel = heap_open(AttributeRelationId, RowExclusiveLock);

tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);

if (!HeapTupleIsValid(tuple))

ereport(ERROR,

(errcode(ERRCODE_UNDEFINED_COLUMN),

errmsg("column \"%s\" of relation \"%s\" does not exist",

colName, RelationGetRelationName(rel))));

/* Prevent them from altering a system attribute */

atttableform = (Form_pg_attribute) GETSTRUCT(tuple);

if (atttableform->attnum <= 0)

ereport(ERROR,

(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),

errmsg("cannot alter system column \"%s\"", colName)));

/* Initialize buffers for new tuple values */

memset(repl_val, 0, sizeof(repl_val));

memset(repl_null, false, sizeof(repl_null));

memset(repl_repl, false, sizeof(repl_repl));

/* Extract the current options */

datum = SysCacheGetAttr(ATTNAME,

tuple,

Anum_pg_attribute_attfdwoptions,

&isnull);

if (isnull)

datum = PointerGetDatum(NULL);

/* Transform the options */

datum = transformGenericOptions(AttributeRelationId,

datum,

options,

fdw->fdwvalidator);

if (PointerIsValid(DatumGetPointer(datum)))

repl_val[Anum_pg_attribute_attfdwoptions - 1] = datum;

else

repl_null[Anum_pg_attribute_attfdwoptions - 1] = true;

repl_repl[Anum_pg_attribute_attfdwoptions - 1] = true;

/* Everything looks good - update the tuple */

newtuple = heap_modify_tuple(tuple, RelationGetDescr(attrel),

repl_val, repl_null, repl_repl);

ReleaseSysCache(tuple);

simple_heap_update(attrel, &newtuple->t_self, newtuple);

CatalogUpdateIndexes(attrel, newtuple);

heap_close(attrel, RowExclusiveLock);

heap_freetuple(newtuple);

}