245 lines
6.8 KiB
Go
245 lines
6.8 KiB
Go
package migrate
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import (
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"context"
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"sort"
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"strings"
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"github.com/gogf/gf/v2/database/gdb"
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)
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// ============================== 源库结构内省 ==============================
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// listTables 查询源库表清单
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//
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// 受白名单过滤，按表名排序以保证结果可复现
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func listTables(ctx context.Context, db gdb.DB, whitelist []string) ([]string, error) {
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tables, err := db.Tables(ctx)
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if err != nil {
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return nil, err
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}
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if len(whitelist) > 0 {
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allow := make(map[string]bool, len(whitelist))
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for _, t := range whitelist {
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allow[strings.TrimSpace(t)] = true
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}
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filtered := make([]string, 0, len(tables))
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for _, t := range tables {
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if allow[t] {
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filtered = append(filtered, t)
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}
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}
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tables = filtered
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}
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sort.Strings(tables)
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return tables, nil
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}
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// introspectTable 单表全量内省
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//
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// 采集列信息（含注释、默认值、自增、主键）、二级索引与表注释
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func introspectTable(ctx context.Context, db gdb.DB, dialect, table string) (*TableMeta, error) {
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fields, err := db.TableFields(ctx, table)
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if err != nil {
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return nil, err
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}
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meta := &TableMeta{Name: table}
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// TableFields 返回 map，按 Index 排序还原物理列序
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sorted := make([]*gdb.TableField, 0, len(fields))
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for _, f := range fields {
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sorted = append(sorted, f)
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}
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sort.Slice(sorted, func(i, j int) bool { return sorted[i].Index < sorted[j].Index })
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for _, f := range sorted {
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typ, length, scale, enumVals := normalizeType(dialect, f.Type)
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meta.Columns = append(meta.Columns, ColumnMeta{
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Name: f.Name,
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Type: typ,
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Length: length,
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Scale: scale,
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EnumVals: enumVals,
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Nullable: f.Null,
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Default: cleanDefault(dialect, f.Default),
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AutoInc: isAutoInc(f.Extra),
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Comment: f.Comment,
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IsPK: strings.EqualFold(f.Key, "PRI") || strings.EqualFold(f.Key, "pri"),
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})
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}
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// 索引与表注释（方言相关）
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switch dialect {
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case "mysql":
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if err = introspectIndexesMySQL(ctx, db, table, meta); err != nil {
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return nil, err
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}
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meta.Comment = tableCommentMySQL(ctx, db, table)
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case "pgsql":
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if err = introspectIndexesPgsql(ctx, db, table, meta); err != nil {
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return nil, err
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}
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meta.Comment = tableCommentPgsql(ctx, db, table)
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default:
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// 其余方言：主键经列元数据已识别，二级索引降级跳过（首期实测链路 mysql→pgsql）
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}
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// 统一索引命名（迁移后全库一种规则，见 normalizeIndexName）
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normalizeIndexes(meta)
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return meta, nil
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}
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// normalizeIndexes 归一化二级索引名
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//
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// 主键随建表落地，不包含在索引集合中
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func normalizeIndexes(meta *TableMeta) {
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for i := range meta.Indexes {
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idx := &meta.Indexes[i]
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idx.Name = normalizeIndexName(meta.Name, idx.Unique, idx.Columns)
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}
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}
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// normalizeIndexName 统一索引命名
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//
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// 唯一索引使用 uk_ 前缀，普通索引使用 idx_ 前缀，后接表名与列名；
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// 名称超过 63 字符时截断，兼容多数数据库的索引名长度上限
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func normalizeIndexName(table string, unique bool, cols []string) string {
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prefix := "idx"
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if unique {
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prefix = "uk"
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}
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name := prefix + "_" + table + "_" + strings.Join(cols, "_")
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if len(name) > 63 {
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name = name[:63]
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}
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return name
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}
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// isAutoInc 判断是否自增列
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//
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// 兼容 MySQL 的 auto_increment 以及 PostgreSQL、SQL Server 的 identity
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func isAutoInc(extra string) bool {
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e := strings.ToLower(extra)
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return strings.Contains(e, "auto_increment") || strings.Contains(e, "identity")
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}
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// introspectIndexesMySQL 采集 MySQL 索引
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//
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// 主键写入列元数据，其余二级索引写入索引集合
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func introspectIndexesMySQL(ctx context.Context, db gdb.DB, table string, meta *TableMeta) error {
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rows, err := db.Ctx(ctx).Raw("SHOW INDEX FROM `" + table + "`").All()
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if err != nil {
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return err
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}
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type idxHolder struct {
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unique bool
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cols []string
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}
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holders := map[string]*idxHolder{}
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order := make([]string, 0)
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for _, r := range rows {
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name := r["Key_name"].String()
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h, ok := holders[name]
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if !ok {
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h = &idxHolder{unique: r["Non_unique"].Int() == 0}
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holders[name] = h
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order = append(order, name)
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}
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h.cols = append(h.cols, r["Column_name"].String())
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}
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for _, name := range order {
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h := holders[name]
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if name == "PRIMARY" {
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for i := range meta.Columns {
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for _, c := range h.cols {
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if meta.Columns[i].Name == c {
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meta.Columns[i].IsPK = true
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}
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}
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}
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continue
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}
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meta.Indexes = append(meta.Indexes, IndexMeta{Unique: h.unique, Name: name, Columns: h.cols})
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}
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return nil
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}
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// tableCommentMySQL 查询 MySQL 表注释
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func tableCommentMySQL(ctx context.Context, db gdb.DB, table string) string {
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row, err := db.Ctx(ctx).Raw(
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"SELECT TABLE_COMMENT FROM information_schema.TABLES WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = ?", table,
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).One()
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if err != nil || len(row) == 0 {
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return ""
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}
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return row["TABLE_COMMENT"].String()
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}
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// introspectIndexesPgsql 采集 PostgreSQL 索引
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//
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// 主键写入列元数据，其余二级索引写入索引集合
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func introspectIndexesPgsql(ctx context.Context, db gdb.DB, table string, meta *TableMeta) error {
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rows, err := db.Ctx(ctx).Raw(
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"SELECT indexname, indexdef FROM pg_indexes WHERE schemaname = current_schema() AND tablename = ?", table,
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).All()
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if err != nil {
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return err
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}
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for _, r := range rows {
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name := r["indexname"].String()
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def := r["indexdef"].String()
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cols := parsePgIndexCols(def)
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if len(cols) == 0 {
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continue
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}
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if name == table+"_pkey" {
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for i := range meta.Columns {
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for _, c := range cols {
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if meta.Columns[i].Name == c {
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meta.Columns[i].IsPK = true
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}
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}
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}
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continue
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}
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meta.Indexes = append(meta.Indexes, IndexMeta{
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Unique: strings.Contains(strings.ToUpper(def), "UNIQUE"),
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Name: name,
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Columns: cols,
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})
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}
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return nil
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}
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// parsePgIndexCols 从建索引语句中提取列清单
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//
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// 取括号内内容按逗号切分，跳过表达式部分
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func parsePgIndexCols(def string) []string {
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start := strings.Index(def, "(")
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end := strings.LastIndex(def, ")")
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if start < 0 || end <= start {
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return nil
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}
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parts := strings.Split(def[start+1:end], ",")
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cols := make([]string, 0, len(parts))
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for _, p := range parts {
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p = strings.TrimSpace(p)
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// 表达式索引（如 lower(name)）取首标识符，跳过复杂表达式
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if i := strings.IndexAny(p, " ("); i > 0 {
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p = p[:i]
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}
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p = strings.Trim(p, `"`)
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if p != "" {
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cols = append(cols, p)
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}
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}
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return cols
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}
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// tableCommentPgsql 查询 PostgreSQL 表注释
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func tableCommentPgsql(ctx context.Context, db gdb.DB, table string) string {
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row, err := db.Ctx(ctx).Raw(
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"SELECT obj_description(c.oid) AS comment FROM pg_class c JOIN pg_namespace n ON n.oid = c.relnamespace WHERE n.nspname = current_schema() AND c.relname = ?", table,
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).One()
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if err != nil || len(row) == 0 {
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return ""
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}
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return row["comment"].String()
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}
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