enhance mapping for ORM sharding

2023-03-04 19:17:16 +00:00 · 2012-05-06 21:08:23 +08:00
parent 972175f236 d8ecb756a7
commit c68a831224
10 changed files with 371 additions and 22 deletions
@@ -0,0 +1,63 @@
+package com.alibaba.druid.bvt.mapping;
+
+import junit.framework.TestCase;
+
+import com.alibaba.druid.mapping.Entity;
+import com.alibaba.druid.mapping.MappingEngine;
+import com.alibaba.druid.mapping.Property;
+import com.alibaba.druid.mapping.spi.MappingVisitor;
+import com.alibaba.druid.mapping.spi.PropertyValue;
+import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
+import com.alibaba.druid.sql.ast.statement.SQLExprTableSource;
+import com.alibaba.druid.sql.ast.statement.SQLTableSource;
+
+
+public class MySqlMappingShardingTest extends TestCase {
+    MappingEngine engine = new ShardingMappingEngine();
+
+    protected void setUp() throws Exception {
+        Entity entity = new Entity();
+        entity.setName("用户");
+        entity.setTableName("user");
+
+        entity.addProperty(new Property("名称", "", "uid"));
+        entity.addProperty(new Property("昵称", "", "name"));
+
+        engine.addEntity(entity);
+    }
+    
+    public void test_0 () throws Exception {
+        String oql = "select * from 用户 u where u.名称 = 'a'";
+        
+        String sql = engine.explainToSelectSQL(oql);
+        
+        System.out.println(sql);
+    }
+    
+    public static class ShardingMappingEngine extends MappingEngine {
+        public void afterResole(MappingVisitor visitor) {
+            String shardingTableName = null;
+            for (PropertyValue entry : visitor.getPropertyValues()) {
+                Entity entity = entry.getEntity();
+                Property property = entry.getProperty();
+                Object value = entry.getValue();
+                
+                if ("用户".equals(entity.getName()) && "名称".equals(property.getName())) {
+                    if ("a".equals(value)) {
+                        shardingTableName = "user_a";
+                    } else {
+                        shardingTableName = "user_x";
+                    }
+                }
+            }
+            
+            for (SQLTableSource tableSource : visitor.getTableSources().values()) {
+                Entity entity = (Entity) tableSource.getAttribute("mapping.entity");
+                if (entity != null && "用户".equals(entity.getName())) {
+                    SQLExprTableSource exprTableSource = (SQLExprTableSource) tableSource;
+                    exprTableSource.setExpr(new SQLIdentifierExpr(shardingTableName));
+                }
+            }
+        }
+    }
+}