🐛 fix(db): 修复Oracle同义词字段注释回填

- 元数据查不到列定义时补查 ALL_SYNONYMS 解析真实表
- 对解析出的 owner 和 table 继续回查列注释与主键信息
- 新增 SBDEV 指向 DEV.PERSON_INFO 的字段注释回归测试

internal/db/oracle_get_tables_test.go

@@ -112,6 +112,60 @@ func TestOracleGetColumnsIncludesColumnComments(t *testing.T) {
 	}
 }
 
+func TestOracleGetColumnsResolvesSynonymTargetComments(t *testing.T) {
+	t.Parallel()
+
+	dbConn, state := openOracleRecordingDB(t)
+	state.mu.Lock()
+	state.disableDefaultTabColumns = true
+	state.queryResults[buildOracleSynonymLookupQuery("SBDEV", "PERSON_INFO")] = oracleRecordingQueryResult{
+		columns: []string{"TABLE_OWNER", "TABLE_NAME"},
+		rows: [][]driver.Value{
+			{"DEV", "PERSON_INFO"},
+		},
+	}
+	state.queryResults[buildOracleColumnsQuery("DEV", "PERSON_INFO")] = oracleRecordingQueryResult{
+		columns: []string{"COLUMN_NAME", "DATA_TYPE", "NULLABLE", "DATA_DEFAULT", "COLUMN_KEY", "COMMENT"},
+		rows: [][]driver.Value{
+			{"PID", "CHAR", "NO", nil, "PRI", "个人标识"},
+			{"XM", "VARCHAR2", "YES", nil, "", "姓名"},
+		},
+	}
+	state.mu.Unlock()
+
+	oracleDB := &OracleDB{conn: dbConn}
+	columns, err := oracleDB.GetColumns("SBDEV", "PERSON_INFO")
+	if err != nil {
+		t.Fatalf("GetColumns 返回错误: %v", err)
+	}
+	if len(columns) != 2 {
+		t.Fatalf("expected synonym target columns, got %#v", columns)
+	}
+	if columns[0].Name != "PID" || columns[0].Comment != "个人标识" || columns[0].Key != "PRI" {
+		t.Fatalf("expected first synonym column metadata from DEV.PERSON_INFO, got %#v", columns[0])
+	}
+	if columns[1].Name != "XM" || columns[1].Comment != "姓名" {
+		t.Fatalf("expected second synonym column comment from DEV.PERSON_INFO, got %#v", columns[1])
+	}
+
+	queries := state.snapshotQueries()
+	if len(queries) < 3 {
+		t.Fatalf("expected direct metadata probe + synonym lookup + target metadata probe, got %v", queries)
+	}
+	if queries[0] != buildOracleColumnsQuery("SBDEV", "PERSON_INFO") {
+		t.Fatalf("expected first metadata probe to use synonym owner, got %v", queries)
+	}
+	if !slices.Contains(queries, buildOracleSynonymLookupQuery("SBDEV", "PERSON_INFO")) {
+		t.Fatalf("expected synonym lookup against all_synonyms, got %v", queries)
+	}
+	if !slices.Contains(queries, buildOracleColumnsQuery("DEV", "PERSON_INFO")) {
+		t.Fatalf("expected metadata probe against resolved target table, got %v", queries)
+	}
+	if slices.Contains(queries, `SELECT * FROM "SBDEV"."PERSON_INFO" WHERE 1 = 0`) {
+		t.Fatalf("expected synonym metadata to resolve before falling back to empty-select inference, got %v", queries)
+	}
+}
+
 func TestOracleColumnsQueryFiltersPrimaryKeyLookupByTargetTable(t *testing.T) {
 	t.Parallel()
 

internal/db/oracle_impl.go

@@ -384,6 +384,18 @@ func (o *OracleDB) GetColumns(dbName, tableName string) ([]connection.ColumnDefi
 
 		return parseOracleColumns(data), nil
 	}
+	for _, target := range o.lookupOracleSynonymTargets(dbName, tableName) {
+		query := buildOracleColumnsQuery(target.schema, target.table)
+		data, _, err := o.Query(query)
+		if err != nil {
+			return nil, err
+		}
+		if len(data) == 0 {
+			continue
+		}
+
+		return parseOracleColumns(data), nil
+	}
 	if columns, err := o.inferOracleColumnsFromSelect(dbName, tableName); err == nil && len(columns) > 0 {
 		return columns, nil
 	}
@@ -718,6 +730,61 @@ func oracleMetadataNamePairs(dbName string, tableName string) []oracleMetadataNa
 	return pairs
 }
 
+func (o *OracleDB) lookupOracleSynonymTargets(dbName string, tableName string) []oracleMetadataNamePair {
+	targets := make([]oracleMetadataNamePair, 0, 4)
+	seen := map[string]struct{}{}
+	add := func(schema string, table string) {
+		key := schema + "\x00" + table
+		if strings.TrimSpace(table) == "" {
+			return
+		}
+		if _, exists := seen[key]; exists {
+			return
+		}
+		seen[key] = struct{}{}
+		targets = append(targets, oracleMetadataNamePair{schema: schema, table: table})
+	}
+
+	for _, candidate := range oracleMetadataNamePairs(dbName, tableName) {
+		data, _, err := o.Query(buildOracleSynonymLookupQuery(candidate.schema, candidate.table))
+		if err != nil {
+			continue
+		}
+		for _, row := range data {
+			targetSchema := oracleRowString(row, "TABLE_OWNER", "table_owner")
+			targetTable := oracleRowString(row, "TABLE_NAME", "table_name")
+			for _, target := range oracleMetadataNamePairs(targetSchema, targetTable) {
+				add(target.schema, target.table)
+			}
+			if strings.TrimSpace(targetTable) != "" {
+				break
+			}
+		}
+	}
+
+	return targets
+}
+
+func buildOracleSynonymLookupQuery(schema string, table string) string {
+	metadataTableName := escapeOracleMetadataLiteralExact(table)
+	if strings.TrimSpace(schema) == "" {
+		return fmt.Sprintf(`SELECT table_owner AS "TABLE_OWNER", table_name AS "TABLE_NAME"
+FROM all_synonyms
+WHERE synonym_name = '%s'
+  AND db_link IS NULL
+  AND (owner = USER OR owner = 'PUBLIC')
+ORDER BY CASE WHEN owner = USER THEN 0 WHEN owner = 'PUBLIC' THEN 1 ELSE 2 END`, metadataTableName)
+	}
+
+	metadataSchemaName := escapeOracleMetadataLiteralExact(schema)
+	return fmt.Sprintf(`SELECT table_owner AS "TABLE_OWNER", table_name AS "TABLE_NAME"
+FROM all_synonyms
+WHERE synonym_name = '%s'
+  AND db_link IS NULL
+  AND owner IN ('%s', 'PUBLIC')
+ORDER BY CASE WHEN owner = '%s' THEN 0 WHEN owner = 'PUBLIC' THEN 1 ELSE 2 END`, metadataTableName, metadataSchemaName, metadataSchemaName)
+}
+
 func buildOracleColumnsQuery(schema string, table string) string {
 	metadataTableName := escapeOracleMetadataLiteralExact(table)
 	metadataSchemaName := escapeOracleMetadataLiteralExact(schema)