attrelid
|
oid
|
Table to which a column belongs
|
attname
|
name
|
Column name
|
atttypid
|
oid
|
Column type
|
attstattarget
|
integer
|
Level of details of statistics collected for this column by ANALYZE.
- The value 0 indicates that no statistics should be collected.
- A negative value indicates that the system default statistic object is used.
- The exact meaning of positive values is data type-dependent.
For scalar data types, attstattarget is both the target number of "most common values" to collect, and the target number of histogram bins to create.
|
attlen
|
smallint
|
Copy of pg_type.typlen in the column's type
|
attnum
|
smallint
|
Number of the column
|
attndims
|
integer
|
Number of dimensions if the column is an array (0 in other cases)
|
attcacheoff
|
integer
|
This column is always set to –1 on disks. When it is loaded into a row descriptor in the memory, it may be updated to cache the offset of the columns in the row.
|
atttypmod
|
integer
|
Type-specific data supplied at the table creation time (for example, the maximum length of a varchar column). This column is used as the third parameter when passing to type-specific input functions and length coercion functions. The value will generally be –1 for types that do not need atttypmod.
|
attbyval
|
Boolean
|
Copy of pg_type.typbyval of this column's type
|
attstorage
|
"char"
|
Copy of pg_type.typstorage of this column's type
|
attalign
|
"char"
|
Copy of pg_type.typalign of this column's type
|
attnotnull
|
Boolean
|
A non-null constraint. It is possible to change this column to enable or disable the constraint.
|
atthasdef
|
Boolean
|
This column has a default value, in which case there will be a corresponding entry in the PG_ATTRDEF table that actually defines the value.
|
attisdropped
|
Boolean
|
Indicates that this column has been deleted and is no longer valid. A deleted column is still physically present in the table but is ignored by the analyzer, so it cannot be accessed through SQL.
|
attislocal
|
Boolean
|
Indicates that this column is locally defined in the relationship. Note that a column can be locally defined and inherited simultaneously.
|
attcmprmode
|
tinyint
|
Compressed modes for a specific column. The compressed mode includes: - ATT_CMPR_NOCOMPRESS
- ATT_CMPR_DELTA
- ATT_CMPR_DICTIONARY
- ATT_CMPR_PREFIX
- ATT_CMPR_NUMSTR
|
attinhcount
|
integer
|
Number of direct ancestors that this column has. A column with an ancestor cannot be dropped nor renamed.
|
attcollation
|
oid
|
Defined collation of a column
|
attacl
|
aclitem[]
|
Permissions for column-level access
|
attoptions
|
text[]
|
Column attribute. Currently, the following attributes are supported:
n_distinct: number of distinct values of a column (excluding subtables).
n_distinct_inherited: number of distinct values of a column (including subtables).
|
attfdwoptions
|
text[]
|
Column attribute of a foreign table. Currently, dist_fdw, file_fdw, and log_fdw do not use foreign table column attributes.
|
attinitdefval
|
bytea
|
attinitdefval stores the default value expression. ADD COLUMN in the row-store table must use this column.
|
attkvtype
|
tinyint
|
Specifies the key value type for a column. Value:
0. ATT_KV_UNDEFINED: default value
1. ATT_KV_TAG: dimension
2. ATT_KV_FIELD: indicator
3. ATT_KV_TIMETAG: time column
|