[Oracle]ALL_CONSTRAINTS

Column	Datatype	NULL	Description
OWNER	VARCHAR2(30)	NOT NULL	Owner of the constraint definition
CONSTRAINT_NAME	VARCHAR2(30)	NOT NULL	Name of the constraint definition
CONSTRAINT_TYPE	VARCHAR2(1)		Type of the constraint definition: C - Check constraint on a table P - Primary key U - Unique key R - Referential integrity V - With check option, on a view O - With read only, on a view H - Hash expression F - Constraint that involves a REF column S - Supplemental logging
TABLE_NAME	VARCHAR2(30)	NOT NULL	Name associated with the table (or view) with the constraint definition
SEARCH_CONDITION	LONG		Text of search condition for a check constraint
R_OWNER	VARCHAR2(30)		Owner of the table referred to in a referential constraint
R_CONSTRAINT_NAME	VARCHAR2(30)		Name of the unique constraint definition for the referenced table
DELETE_RULE	VARCHAR2(9)		Delete rule for a referential constraint: CASCADE SET NULL NO ACTION
STATUS	VARCHAR2(8)		Enforcement status of the constraint: ENABLED DISABLED
DEFERRABLE	VARCHAR2(14)		Indicates whether the constraint is deferrable (DEFERRABLE) or not (NOT DEFERRABLE)
DEFERRED	VARCHAR2(9)		Indicates whether the constraint was initially deferred (DEFERRED) or not (IMMEDIATE)
VALIDATED	VARCHAR2(13)		Indicates whether all data obeys the constraint (VALIDATED) or not (NOT VALIDATED)
GENERATED	VARCHAR2(14)		Indicates whether the name of the constraint is user-generated (USER NAME) or system-generated (GENERATED NAME)
BAD	VARCHAR2(3)		Indicates whether this constraint specifies a century in an ambiguous manner (BAD) or not (NULL). To avoid errors resulting from this ambiguity, rewrite the constraint using the TO_DATE function with a four-digit year. See Also: the TO_DATE function in Oracle Database SQL Language Reference and Oracle Database Advanced Application Developer's Guide
RELY	VARCHAR2(4)		Indicates whether an enabled constraint is enforced (RELY) or unenforced (NULL) See Also: the constraints in Oracle Database SQL Language Reference
LAST_CHANGE	DATE		When the constraint was last enabled or disabled
INDEX_OWNER	VARCHAR2(30)		Name of the user owning the index
INDEX_NAME	VARCHAR2(30)		Name of the index (only shown for unique and primary-key constraints)
INVALID	VARCHAR2(7)		Indicates whether the constraint is invalid (INVALID) or not (NULL)
VIEW_RELATED	VARCHAR2(14)		Indicates whether the constraint depends on a view (DEPEND ON VIEW) or not (NULL)

테이블의 PK, FK등을 찾을수 있다. 테이블에서 지정되어있는 not null 여부도 이 테이블을 조회해보면 확인할 수 있다.

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