如何獲得字段外鍵（表和字段）php mysqli

Question

我怎樣才能獲得外鍵字段在phpMyAdmin中使用php和mysqli？
見照片：

Answer 1

所有的約束都列在INFORMATION_SCHEMA.TABLE_CONSTRAINTS：

mysql> create table test.foo (id int primary key); 
mysql> create table test.bar (fooid int, foreign key (fooid) references foo(id)); 

mysql> select * from information_schema.table_constraints 
    where constraint_schema = 'test'\G 
*************************** 1. row *************************** 
CONSTRAINT_CATALOG: def 
CONSTRAINT_SCHEMA: test 
    CONSTRAINT_NAME: bar_ibfk_1 
     TABLE_SCHEMA: test 
     TABLE_NAME: bar 
    CONSTRAINT_TYPE: FOREIGN KEY 
*************************** 2. row *************************** 
CONSTRAINT_CATALOG: def 
CONSTRAINT_SCHEMA: test 
    CONSTRAINT_NAME: PRIMARY 
     TABLE_SCHEMA: test 
     TABLE_NAME: foo 
    CONSTRAINT_TYPE: PRIMARY KEY 

而且所有這些約束的列是INFORMATION_SCHEMA.KEY_COLUMN_USAGE：

mysql> select * from information_schema.key_column_usage 
    where constraint_schema = 'test'\G 
*************************** 1. row *************************** 
      CONSTRAINT_CATALOG: def 
      CONSTRAINT_SCHEMA: test 
       CONSTRAINT_NAME: bar_ibfk_1 
       TABLE_CATALOG: def 
       TABLE_SCHEMA: test 
        TABLE_NAME: bar 
        COLUMN_NAME: fooid 
      ORDINAL_POSITION: 1 
POSITION_IN_UNIQUE_CONSTRAINT: 1 
     REFERENCED_TABLE_SCHEMA: test 
     REFERENCED_TABLE_NAME: foo 
     REFERENCED_COLUMN_NAME: id 
*************************** 2. row *************************** 
      CONSTRAINT_CATALOG: def 
      CONSTRAINT_SCHEMA: test 
       CONSTRAINT_NAME: PRIMARY 
       TABLE_CATALOG: def 
       TABLE_SCHEMA: test 
        TABLE_NAME: foo 
        COLUMN_NAME: id 
      ORDINAL_POSITION: 1 
POSITION_IN_UNIQUE_CONSTRAINT: NULL 
     REFERENCED_TABLE_SCHEMA: NULL 
     REFERENCED_TABLE_NAME: NULL 
     REFERENCED_COLUMN_NAME: NULL