src/zh/UserGuide/dev-1.3/Tools-System/Schema-Export-Tool.md

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# 元数据导出

## 1. 功能概述

元数据导出工具 `export-schema.sh/bat` 位于tools 目录下，能够将 IoTDB 中指定数据库下的元数据导出为csv文件。

> V1.3.3 版本起支持

## 2. 功能详解

### 2.1 参数介绍

| 参数缩写           | 参数全称                   | 参数含义                                            | 是否为必填项 | 默认值                                   |
| -------------------- |------------------------|-------------------------------------------------|--------|---------------------------------------|
| `-h`           | `-- host`              | 主机名                                             | 否      | 127.0.0.1                             |
| `-p`           | `--port`               | 端口号                                             | 否      | 6667                                  |
| `-u`           | `--username`           | 用户名                                             | 否      | root                                  |
| `-pw`          | `--password`           | 密码，自 V2.0.9-beta 起支持隐藏输入                        | 否      | root                                  |
| `-t`           | `--target`             | 指定输出文件的目标文件夹，如果路径不存在新建文件夹                       | 是      |                                       |
| `-path`        | `--path_pattern`       | 指定导出元数据的path  pattern                           | 是      |                                       |
| `-pf`          | `--path_pattern_file`  | 指定导出文件的名称。                                      | 否      |                     |
| `-lpf`         | `--lines_per_file`     | 指定导出的dump文件最大行数                                 | 否      | `10000`                               |
| `-timeout`     | `--queryTimeout`       | 会话查询的超时时间(ms)                                   | 否      | -1范围：-1～Long. max=9223372036854775807 |
| `-help`        | `--help`               | 显示帮助信息                                          | 否      |                                       |

### 2.2 运行命令

```Bash
Shell
# Unix/OS X
> tools/export-schema.sh [-h <host>] [-p <port>] [-u <username>] [-pw <password>] -t <targetDir>
       [-path <exportPathPattern>] [-pf <exportPathPatternFile>] [-lpf <linesPerFile>]
       [-timeout <timeout>] [-help]

# Windows
> tools\export-schema.bat [-h <host>] [-p <port>] [-u <username>] [-pw <password>] -t <targetDir>
       [-path <exportPathPattern>] [-pf <exportPathPatternFile>] [-lpf <linesPerFile>]
       [-timeout <timeout>] [-help]
```

### 2.3 运行示例

```Bash
# 导出 root.ln路径下的元数据
./export-schema.sh -t /home/ -path "root.ln.**"

# 导出结果内容格式如下
Timeseries,Alias,DataType,Encoding,Compression
root.ln.wf02.wt02.status,,BOOLEAN,RLE,LZ4
root.ln.wf02.wt02.hardware,,TEXT,PLAIN,LZ4
```