fix issue #3286 (#3289)

contrib/drivers/pgsql/pgsql_table_fields.go

@@ -0,0 +1,78 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
+package pgsql
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/gogf/gf/v2/database/gdb"
+	"github.com/gogf/gf/v2/util/gutil"
+)
+
+var (
+	tableFieldsSqlTmp = `
+SELECT a.attname AS field, t.typname AS type,a.attnotnull as null,
+    (case when d.contype is not null then 'pri' else '' end)  as key
+      ,ic.column_default as default_value,b.description as comment
+      ,coalesce(character_maximum_length, numeric_precision, -1) as length
+      ,numeric_scale as scale
+FROM pg_attribute a
+         left join pg_class c on a.attrelid = c.oid
+         left join pg_constraint d on d.conrelid = c.oid and a.attnum = d.conkey[1]
+         left join pg_description b ON a.attrelid=b.objoid AND a.attnum = b.objsubid
+         left join pg_type t ON a.atttypid = t.oid
+         left join information_schema.columns ic on ic.column_name = a.attname and ic.table_name = c.relname
+WHERE c.relname = '%s' and a.attisdropped is false and a.attnum > 0
+ORDER BY a.attnum`
+)
+
+func init() {
+	tableFieldsSqlTmp = formatSqlTmp(tableFieldsSqlTmp)
+}
+
+// TableFields retrieves and returns the fields' information of specified table of current schema.
+func (d *Driver) TableFields(ctx context.Context, table string, schema ...string) (fields map[string]*gdb.TableField, err error) {
+	var (
+		result     gdb.Result
+		link       gdb.Link
+		usedSchema = gutil.GetOrDefaultStr(d.GetSchema(), schema...)
+		// TODO duplicated `id` result?
+		structureSql = fmt.Sprintf(tableFieldsSqlTmp, table)
+	)
+	if link, err = d.SlaveLink(usedSchema); err != nil {
+		return nil, err
+	}
+	result, err = d.DoSelect(ctx, link, structureSql)
+	if err != nil {
+		return nil, err
+	}
+	fields = make(map[string]*gdb.TableField)
+	var (
+		index = 0
+		name  string
+		ok    bool
+	)
+	for _, m := range result {
+		name = m["field"].String()
+		// Filter duplicated fields.
+		if _, ok = fields[name]; ok {
+			continue
+		}
+		fields[name] = &gdb.TableField{
+			Index:   index,
+			Name:    name,
+			Type:    m["type"].String(),
+			Null:    !m["null"].Bool(),
+			Key:     m["key"].String(),
+			Default: m["default_value"].Val(),
+			Comment: m["comment"].String(),
+		}
+		index++
+	}
+	return fields, nil
+}