如何在MariaDB中选择所有外键

Question

我对MS Sql Server有以下查询，

SELECT  DISTINCT
              OnTable.name as OnTable, 
              AgainstTable.name as AgainstTable
    FROM sysforeignkeys fk
            INNER JOIN sysobjects onTable      ON fk.fkeyid = onTable.id
            INNER JOIN sysobjects againstTable ON fk.rkeyid = againstTable.id

现在，我需要在MariaDB中创建一个等效查询。基本上，我需要知道MariaDB中的哪些表可以替换sysforeignkeys和sysobjects？

Answer 1

您在这里：

my_data2 <- my_data %>% 
  group_by(group) %>% 
  nest() %>% 
  mutate(km_cluster = map(data, ~kmeans(.x, 3))) %>%
  mutate(data = map2(data, km_cluster, ~.x %>% mutate(cluster = .y[["cluster"]])),
         data = map2(data, km_cluster, ~left_join(.x, 
                                                  .y %>%
                                                    pluck("centers") %>%
                                                    as_data_frame() %>%
                                                    rowid_to_column() %>%
                                                    rename(x_center = x, y_center = y), 
                                                  by = c("cluster" = "rowid"))))

好吧，您的查询显示的细节较少。这是等效的内容：

select
    fk.constraint_name, 
    c.ordinal_position,
    c.table_schema,
    c.table_name,
    c.column_name,
    c.referenced_table_schema,
    c.referenced_table_name,
    c.referenced_column_name
  from information_schema.table_constraints fk
  join information_schema.key_column_usage c 
    on c.constraint_name = fk.constraint_name
  where fk.constraint_type = 'FOREIGN KEY';