首先寻找PK的索引名称（pk_idx列）
select c.constrname, c.constrtype as tp , c.idxname as pk_idx , t2.tabname, c2.idxnamefrom sysconstraints c, systables t, outer (sysreferences r, systables t2, sysconstraints c2)where t.tabname = "asamembr" and t.tabid = c.tabid and r.constrid = c.constrid and t2.tabid = r.ptabid and c2.constrid = r.constrid
其中的构造型：
constrtype CHAr(1) Code identifying the constraint type:
C = Check constraint
N = Not NULL
P = Primary key
R = Referential
T = Table
U = Unique
然后，检查索引列（查找与PK约束相同的索引名称）：
select unique t.tabname , i.idxname , i.idxtype , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part1 ) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part2 ) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part3 ) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part4 ) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part5 ) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part6 ) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part7 ) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part8 ) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part9 ) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part10) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part11) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part12) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part13) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part14) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part15) , (select c.colname from syscolumns c where c.tabid = i.tabid and c.colno = i.part16) from sysindexes i , systables t where i.tabid = t.tabid and t.tabname = "asamembr";
其中idxtype：
idxtype CHAr(1) Index type:
U = Unique
D = Duplicates allowed
G = Nonbitmap generali
g = Bitmap generalized
u = unique, bitmap
d = nonunique, bitmap
在Informix在线手册中搜索“
sysconstraints”或“ sysindexes”
