下文为您介绍Oracle及SQL Server两种数据库中查询表主键外键信息的SQL语句写法，供您参考，希望对您学习SQL语句的使用有所启迪。
Oracle:
select o.obj# as objectId, o.name AS tableName, oc.name AS constraintName, decode(c.type#, 1, 'C', 2, 'P', 3, 'U', 4, 'R', 5, 'V', 6, 'O', 7,'C', ' ') as constraintType, col.name AS columnName from sys.con$ oc, sys.con$ rc, sys.obj$ ro,sys.obj$ o, sys.obj$ oi, sys.cdef$ c, sys.col$ col, sys.ccol$ cc, sys.attrcol$ ac where oc.con# = c.con# and c.obj# = o.obj# and c.rcon# = rc.con#(+) and c.enabled = oi.obj#(+) and c.robj# = ro.obj#(+) and c.type# != 8 and c.type# != 12 /* don't include log groups */ 字串9 and c.con# = cc.con# and cc.obj# = col.obj# and cc.intcol# = col.intcol# and cc.obj# = o.obj# and col.obj# = ac.obj#(+) and col.intcol# = ac.intcol#(+) and o.name = 'your table'
SQL Server:
SELECT sysobjects.id objectId, OBJECT_NAME(sysobjects.parent_obj) tableName, sysobjects.name constraintName, sysobjects.xtype AS constraintType, syscolumns.name AS columnName FROM sysobjects INNER JOIN sysconstraints ON sysobjects.xtype in('C', 'F', 'PK', 'UQ', 'D') AND sysobjects.id = sysconstraints.constid LEFT OUTER JOIN syscolumns ON sysconstraints.id = syscolumns.id WHERE OBJECT_NAME(sysobjects.parent_obj)='your table'