Amazon Redshift will no longer support the creation of new Python UDFs starting Patch 198. Existing Python UDFs will continue to function until June 30, 2026. For more information, see the [ blog post ](https://aws.amazon.com/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/). 

# PG\_TABLE\_DEF
<a name="r_PG_TABLE_DEF"></a>

Stores information about table columns.

PG\_TABLE\_DEF only returns information about tables that are visible to the user. If PG\_TABLE\_DEF does not return the expected results, verify that the [search\_path](r_search_path.md) parameter is set correctly to include the relevant schemas.

You can use [SVV\_TABLE\_INFO](r_SVV_TABLE_INFO.md) to view more comprehensive information about a table, including data distribution skew, key distribution skew, table size, and statistics. 

## Table columns
<a name="r_PG_TABLE_DEF-table-columns2"></a>


| Column name  | Data type  | Description  | 
| --- | --- | --- | 
| schemaname | name | Schema name. | 
| tablename | name | Table name. | 
| column | name  | Column name. | 
| type  | text | Datatype of column. | 
| encoding  | character(32)  | Encoding of column. | 
| distkey  | boolean | True if this column is the distribution key for the table. | 
| sortkey | integer  | Order of the column in the sort key. If the table uses a compound sort key, then all columns that are part of the sort key have a positive value that indicates the position of the column in the sort key. If the table uses an interleaved sort key, then each column that is part of the sort key has a value that is alternately positive or negative, where the absolute value indicates the position of the column in the sort key. If 0, the column is not part of a sort key.  | 
| notnull | boolean  | True if the column has a NOT NULL constraint. | 

## Example
<a name="r_PG_TABLE_DEF-example2"></a>

The following example shows the compound sort key columns for the LINEORDER\_COMPOUND table.

```
select "column", type, encoding, distkey, sortkey, "notnull" 
from pg_table_def
where tablename = 'lineorder_compound' 
and sortkey <> 0;

column       | type    | encoding | distkey | sortkey | notnull
-------------+---------+----------+---------+---------+--------
lo_orderkey  | integer | delta32k | false   |       1 | true   
lo_custkey   | integer | none     | false   |       2 | true   
lo_partkey   | integer | none     | true    |       3 | true   
lo_suppkey   | integer | delta32k | false   |       4 | true   
lo_orderdate | integer | delta    | false   |       5 | true   
(5 rows)
```

 The following example shows the interleaved sort key columns for the LINEORDER\_INTERLEAVED table.

```
select "column", type, encoding, distkey, sortkey, "notnull" 
from pg_table_def
where tablename = 'lineorder_interleaved' 
and sortkey <> 0;

column       | type    | encoding | distkey | sortkey | notnull
-------------+---------+----------+---------+---------+--------
lo_orderkey  | integer | delta32k | false   |      -1 | true   
lo_custkey   | integer | none     | false   |       2 | true   
lo_partkey   | integer | none     | true    |      -3 | true   
lo_suppkey   | integer | delta32k | false   |       4 | true   
lo_orderdate | integer | delta    | false   |      -5 | true   
(5 rows)
```

PG\_TABLE\_DEF will only return information for tables in schemas that are included in the search path. For more information, see [search\_path](r_search_path.md).

For example, suppose you create a new schema and a new table, then query PG\_TABLE\_DEF.

```
create schema demo;
create table demo.demotable (one int);
select * from pg_table_def where tablename = 'demotable';

schemaname|tablename|column| type | encoding | distkey | sortkey | notnull 
----------+---------+------+------+----------+---------+---------+--------
```

The query returns no rows for the new table. Examine the setting for `search_path`.

```
show search_path;

  search_path
---------------
 $user, public
(1 row)
```

Add the `demo` schema to the search path and run the query again.

```
set search_path to '$user', 'public', 'demo';

select * from pg_table_def where tablename = 'demotable';

schemaname| tablename |column|  type   | encoding |distkey|sortkey| notnull
----------+-----------+------+---------+----------+-------+-------+--------
demo      | demotable | one  | integer | none     | f     |     0 | f
(1 row)
```