fix(dameng-databases): 修复显示全部库时数据库列表不完整 refs #154

internal/db/dameng_impl.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"net"
 	"net/url"
+	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -204,24 +205,82 @@ func (d *DamengDB) Exec(query string) (int64, error) {
 }
 
 func (d *DamengDB) GetDatabases() ([]string, error) {
-	// DM: List Users/Schemas
-	data, _, err := d.Query("SELECT username FROM dba_users")
-	if err != nil {
-		// Fallback if dba_users not accessible
-		data, _, err = d.Query("SELECT username FROM all_users")
+	// 达梦将「用户/模式」作为数据库列表来源，不同权限下可见口径不同。
+	// 这里采用多查询口径聚合，避免仅依赖单一视图导致“少库”。
+	queries := []string{
+		"SELECT USERNAME AS DATABASE_NAME FROM SYS.DBA_USERS ORDER BY USERNAME",
+		"SELECT USERNAME AS DATABASE_NAME FROM DBA_USERS ORDER BY USERNAME",
+		"SELECT USERNAME AS DATABASE_NAME FROM ALL_USERS ORDER BY USERNAME",
+		"SELECT USERNAME AS DATABASE_NAME FROM USER_USERS",
+		"SELECT DISTINCT OWNER AS DATABASE_NAME FROM ALL_TABLES ORDER BY OWNER",
+	}
+
+	seen := make(map[string]struct{})
+	dbs := make([]string, 0, 64)
+	var lastErr error
+	success := false
+
+	for _, q := range queries {
+		data, _, err := d.Query(q)
 		if err != nil {
-			return nil, err
+			lastErr = err
+			continue
+		}
+		success = true
+		for _, row := range data {
+			name := getDamengRowString(row, "DATABASE_NAME", "USERNAME", "OWNER", "SCHEMA_NAME")
+			if name == "" {
+				// 回退到第一列，兼容驱动返回列名差异。
+				for _, v := range row {
+					text := strings.TrimSpace(fmt.Sprintf("%v", v))
+					if text == "" || strings.EqualFold(text, "<nil>") {
+						continue
+					}
+					name = text
+					break
+				}
+			}
+			if name == "" {
+				continue
+			}
+			key := strings.ToUpper(name)
+			if _, ok := seen[key]; ok {
+				continue
+			}
+			seen[key] = struct{}{}
+			dbs = append(dbs, name)
 		}
 	}
-	var dbs []string
-	for _, row := range data {
-		if val, ok := row["USERNAME"]; ok {
-			dbs = append(dbs, fmt.Sprintf("%v", val))
-		}
+
+	if !success && lastErr != nil {
+		return nil, lastErr
 	}
+
+	sort.Slice(dbs, func(i, j int) bool {
+		return strings.ToUpper(dbs[i]) < strings.ToUpper(dbs[j])
+	})
 	return dbs, nil
 }
 
+func getDamengRowString(row map[string]interface{}, keys ...string) string {
+	if len(row) == 0 {
+		return ""
+	}
+	for _, key := range keys {
+		for k, v := range row {
+			if !strings.EqualFold(strings.TrimSpace(k), strings.TrimSpace(key)) {
+				continue
+			}
+			text := strings.TrimSpace(fmt.Sprintf("%v", v))
+			if text == "" || strings.EqualFold(text, "<nil>") {
+				return ""
+			}
+			return text
+		}
+	}
+	return ""
+}
+
 func (d *DamengDB) GetTables(dbName string) ([]string, error) {
 	query := fmt.Sprintf("SELECT owner, table_name FROM all_tables WHERE owner = '%s' ORDER BY table_name", strings.ToUpper(dbName))
 	if dbName == "" {