写作业的时候发现书上竟然找不到查询约束的语句，百度搜了好久的资料，终于查询成功，在这里记录下来
主键约束
SELECT
tab.
name
AS
[表名],
idx.
name
AS
[主键名称],
col.
name
AS
[主键列名]
FROM
sys.indexes idx
JOIN
sys.index_columns idxCol
ON
(idx.object_id = idxCol.object_id
AND
idx.index_id = idxCol.index_id
AND
idx.is_primary_key = 1)
JOIN
sys.tables tab
ON
(idx.object_id = tab.object_id)
JOIN
sys.columns col
ON
(idx.object_id = col.object_id
AND
idxCol.column_id = col.column_id);
唯一约束
SELECT
tab.
name
AS
[表名],
idx.
name
AS
[约束名称],
col.
name
AS
[约束列名]
FROM
sys.indexes idx
JOIN
sys.index_columns idxCol
ON
(idx.object_id = idxCol.object_id
AND
idx.index_id = idxCol.index_id
AND
idx.is_unique_constraint = 1)
JOIN
sys.tables tab
ON
(idx.object_id = tab.object_id)
JOIN
sys.columns col
ON
(idx.object_id = col.object_id
AND
idxCol.column_id = col.column_id);
外键约束
select
oSub.
name
AS
[子表名称],
fk.
name
AS
[外键名称],
SubCol.
name
AS
[子表列名],
oMain.
name
AS
[主表名称],
MainCol.
name
AS
[主表列名]
from
sys.foreign_keys fk
JOIN
sys.all_objects oSub
ON
(fk.parent_object_id = oSub.object_id)
JOIN
sys.all_objects oMain
ON
(fk.referenced_object_id = oMain.object_id)
JOIN
sys.foreign_key_columns fkCols
ON
(fk.object_id = fkCols.constraint_object_id)
JOIN
sys.columns SubCol
ON
(oSub.object_id = SubCol.object_id
AND
fkCols.parent_column_id = SubCol.column_id)
JOIN
sys.columns MainCol
ON
(oMain.object_id = MainCol.object_id
AND
fkCols.referenced_column_id = MainCol.column_id)
Check
约束
SELECT
tab.
name
AS
[表名],
chk.
name
AS
[
Check
约束名],
col.
name
AS
[列名],
chk.definition
FROM
sys.check_constraints chk
JOIN
sys.tables tab
ON
(chk.parent_object_id = tab.object_id)
JOIN
sys.columns col
ON
(chk.parent_object_id = col.object_id
AND
chk.parent_column_id = col.column_id)