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diff --git "a/\345\273\226\346\263\260\347\216\256/20240904/crebas.sql" "b/\345\273\226\346\263\260\347\216\256/20240904/crebas.sql"
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index 0000000000000000000000000000000000000000..da217fbe4fbccc0d40e44db4b435a7b19d6af6e3
--- /dev/null
+++ "b/\345\273\226\346\263\260\347\216\256/20240904/crebas.sql"
@@ -0,0 +1,88 @@
+/*==============================================================*/
+/* DBMS name:      MySQL 5.0                                    */
+/* Created on:     2024/9/4 21:26:35                            */
+/*==============================================================*/
+
+
+drop table if exists game;
+
+drop table if exists pael;
+
+drop table if exists paelman;
+
+drop table if exists sxx;
+
+drop table if exists uerl;
+
+/*==============================================================*/
+/* Table: game                                                  */
+/*==============================================================*/
+create table game
+(
+   g_id                 int not null,
+   g_name               varchar(10),
+   primary key (g_id)
+);
+
+/*==============================================================*/
+/* Table: pael                                                  */
+/*==============================================================*/
+create table pael
+(
+   g_id                 int not null,
+   p_id                 int not null,
+   primary key (g_id, p_id)
+);
+
+/*==============================================================*/
+/* Table: paelman                                               */
+/*==============================================================*/
+create table paelman
+(
+   p_id                 int not null,
+   s_id                 int,
+   p_name               varchar(10),
+   primary key (p_id)
+);
+
+/*==============================================================*/
+/* Table: sxx                                                   */
+/*==============================================================*/
+create table sxx
+(
+   s_id                 int not null,
+   s_ma                 varchar(18),
+   name                 varchar(10),
+   primary key (s_id)
+);
+
+/*==============================================================*/
+/* Table: uerl                                                  */
+/*==============================================================*/
+create table uerl
+(
+   u_id                 int not null,
+   p_id                 int,
+   u_name               varchar(18),
+   primary key (u_id)
+);
+
+alter table pael add constraint FK_pael foreign key (g_id)
+      references game (g_id) on delete restrict on update restrict;
+
+alter table pael add constraint FK_pael2 foreign key (p_id)
+      references paelman (p_id) on delete restrict on update restrict;
+
+alter table paelman add constraint FK_haye foreign key (s_id)
+      references sxx (s_id) on delete restrict on update restrict;
+
+alter table uerl add constraint FK_have foreign key (p_id)
+      references paelman (p_id) on delete restrict on update restrict;
+      
+INSERT INTO game VALUES (1,"wz"),(2,"ys"),(3,"mc");
+INSERT INTO pael VALUES (1,2),(2,2),(3,1);
+INSERT INTO paelman VALUES (1,1,"zs"),(2,2,"ls");
+INSERT INTO sxx VALUES (1,1884562456,"zs"),(2,46415115,"ls");
+INSERT INTO uerl VALUES (1,1,"46646"),(2,1,"4684668"),(3,2,"486456");
+
+SELECT * FROM uerl as u,paelman as p WHERE u.p_id=p.p_id;
\ No newline at end of file
diff --git "a/\345\273\226\346\263\260\347\216\256/20240904/\347\254\224\350\256\260.md" "b/\345\273\226\346\263\260\347\216\256/20240904/\347\254\224\350\256\260.md"
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index 0000000000000000000000000000000000000000..3e9de9145a12e0d140b1db2fcf75ee75555c81f8
--- /dev/null
+++ "b/\345\273\226\346\263\260\347\216\256/20240904/\347\254\224\350\256\260.md"
@@ -0,0 +1,8 @@
+##表与表的关系##
+  1. 一对一联系(1:1)：一个实体的每个实例只关联另一个实体的一个实例。
+  2. 一对多联系(1:n)：一个实体的每个实例可以关联另一个实体的多个实例。
+  3. 多对多联系(m:n):两个实体的多个实例之间可以相互关联。
+##三大范式##
+  1. 第一范式（1NF）: 确保每个字段只有单一的原子值，不允许重复的组。
+  2. 第二范式（2NF）: 确保每个非主属性完全依赖于主键，消除部分依赖。
+  3. 第三范式（3NF）: 确保每个非主属性直接依赖于主键，消除传递依赖。
\ No newline at end of file