From fb229b21e641d41b19bf839f486687fe97c09254 Mon Sep 17 00:00:00 2001
From: tmlx1990 <tmlx1990@163.com>
Date: Tue, 28 May 2024 00:53:10 +0800
Subject: [PATCH] =?UTF-8?q?mysql=E4=BF=AE=E6=94=B9=E5=88=97=E9=A1=BA?=
 =?UTF-8?q?=E5=BA=8F=E6=B5=8B=E8=AF=95?=
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---
 .../plugin/mysql/builder/MysqlSqlBuilder.java | 56 ++++++++++++++++++-
 1 file changed, 55 insertions(+), 1 deletion(-)

diff --git a/chat2db-server/chat2db-plugins/chat2db-mysql/src/main/java/ai/chat2db/plugin/mysql/builder/MysqlSqlBuilder.java b/chat2db-server/chat2db-plugins/chat2db-mysql/src/main/java/ai/chat2db/plugin/mysql/builder/MysqlSqlBuilder.java
index dc27b5af..3f93993d 100644
--- a/chat2db-server/chat2db-plugins/chat2db-mysql/src/main/java/ai/chat2db/plugin/mysql/builder/MysqlSqlBuilder.java
+++ b/chat2db-server/chat2db-plugins/chat2db-mysql/src/main/java/ai/chat2db/plugin/mysql/builder/MysqlSqlBuilder.java
@@ -93,6 +93,19 @@ public class MysqlSqlBuilder extends DefaultSqlBuilder {
             script.append("\t").append("AUTO_INCREMENT=").append(newTable.getIncrementValue()).append(",\n");
         }
 
+        // 判断是否有删除字段、新增字段及字段位置移动
+        // 判断新增字段
+        List<TableColumn> addColumnList = new ArrayList<>();
+        for (TableColumn tableColumn : newTable.getColumnList()) {
+            if (tableColumn.getEditStatus() != null ?  tableColumn.getEditStatus().equals("ADD") : false) {
+                addColumnList.add(tableColumn);
+            }
+        }
+
+        // 判断移动的字段
+        List<TableColumn> moveColumnList = new ArrayList<>();
+        movedElements(oldTable.getColumnList(), newTable.getColumnList());
+
         // append modify column
         for (TableColumn tableColumn : newTable.getColumnList()) {
             if (StringUtils.isNotBlank(tableColumn.getEditStatus()) && StringUtils.isNotBlank(tableColumn.getColumnType()) && StringUtils.isNotBlank(tableColumn.getName())) {
@@ -110,7 +123,7 @@ public class MysqlSqlBuilder extends DefaultSqlBuilder {
         }
 
         // append reorder column
-        script.append(buildGenerateReorderColumnSql(oldTable, newTable));
+       // script.append(buildGenerateReorderColumnSql(oldTable, newTable));
 
         if (script.length() > 2) {
             script = new StringBuilder(script.substring(0, script.length() - 2));
@@ -151,6 +164,47 @@ public class MysqlSqlBuilder extends DefaultSqlBuilder {
         return sqlBuilder.toString();
     }
 
+    public static List<TableColumn> movedElements(List<TableColumn> original, List<TableColumn> modified) {
+        int[][] dp = new int[original.size() + 1][modified.size() + 1];
+
+        // 构建DP表
+        for (int i = 1; i <= original.size(); i++) {
+            for (int j = 1; j <= modified.size(); j++) {
+                if (original.get(i - 1).getName().equals(modified.get(j - 1).getOldName())) {
+                    dp[i][j] = dp[i - 1][j - 1] + 1;
+                } else {
+                    dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]);
+                }
+            }
+        }
+
+        // 追踪LCS，找出移动了位置的元素
+        List<TableColumn> moved = new ArrayList<>();
+        int i = original.size();
+        int j = modified.size();
+        while (i > 0 && j > 0) {
+            if (original.get(i - 1).equals(modified.get(j - 1))) {
+                i--;
+                j--;
+            } else if (dp[i - 1][j] >= dp[i][j - 1]) {
+                moved.add(original.get(i - 1));
+                // modified List中找到original.get(i-1)的位置
+                System.out.println("Moved elements:"+ original.get(i-1).getName() + " after " + modified.indexOf(original.get(i-1)) );
+                i--;
+            } else {
+                j--;
+            }
+        }
+
+        // 这里添加原始列表中未被包含在LCS中的元素
+        while (i > 0) {
+            moved.add(original.get(i - 1));
+            i--;
+        }
+
+        return moved;
+    }
+
     public String buildGenerateReorderColumnSql(Table oldTable, Table newTable) {
         StringBuilder sql = new StringBuilder();
         int n = 0;