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.definitionFROM 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)原文：https://www.cnblogs.com/caijiaming/p/9959898.html