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| # Node Management | |
| ## Show Child Paths | |
| ``` | |
| SHOW CHILD PATHS pathPattern | |
| ``` | |
| Return all child paths and their node types of all the paths matching pathPattern. | |
| node types: ROOT -> DB INTERNAL -> DATABASE -> INTERNAL -> DEVICE -> TIMESERIES | |
| Example： | |
| * return the child paths of root.ln：show child paths root.ln | |
| ``` | |
| +------------+----------+ | |
| | child paths|node types| | |
| +------------+----------+ | |
| |root.ln.wf01| INTERNAL| | |
| |root.ln.wf02| INTERNAL| | |
| +------------+----------+ | |
| Total line number = 2 | |
| It costs 0.002s | |
| ``` | |
| > get all paths in form of root.xx.xx.xx：show child paths root.xx.xx | |
| ## Show Child Nodes | |
| ``` | |
| SHOW CHILD NODES pathPattern | |
| ``` | |
| Return all child nodes of the pathPattern. | |
| Example： | |
| * return the child nodes of root：show child nodes root | |
| ``` | |
| +------------+ | |
| | child nodes| | |
| +------------+ | |
| | ln| | |
| +------------+ | |
| ``` | |
| * return the child nodes of root.ln：show child nodes root.ln | |
| ``` | |
| +------------+ | |
| | child nodes| | |
| +------------+ | |
| | wf01| | |
| | wf02| | |
| +------------+ | |
| ``` | |
| ## Count Nodes | |
| IoTDB is able to use `COUNT NODES <PathPattern> LEVEL=<INTEGER>` to count the number of nodes at | |
| the given level in current Metadata Tree considering a given pattern. IoTDB will find paths that | |
| match the pattern and counts distinct nodes at the specified level among the matched paths. | |
| This could be used to query the number of devices with specified measurements. The usage are as | |
| follows: | |
| ``` | |
| IoTDB > COUNT NODES root.** LEVEL=2 | |
| IoTDB > COUNT NODES root.ln.** LEVEL=2 | |
| IoTDB > COUNT NODES root.ln.wf01.** LEVEL=3 | |
| IoTDB > COUNT NODES root.**.temperature LEVEL=3 | |
| ``` | |
| As for the above mentioned example and Metadata tree, you can get following results: | |
| ``` | |
| +------------+ | |
| |count(nodes)| | |
| +------------+ | |
| | 4| | |
| +------------+ | |
| Total line number = 1 | |
| It costs 0.003s | |
| +------------+ | |
| |count(nodes)| | |
| +------------+ | |
| | 2| | |
| +------------+ | |
| Total line number = 1 | |
| It costs 0.002s | |
| +------------+ | |
| |count(nodes)| | |
| +------------+ | |
| | 1| | |
| +------------+ | |
| Total line number = 1 | |
| It costs 0.002s | |
| +------------+ | |
| |count(nodes)| | |
| +------------+ | |
| | 2| | |
| +------------+ | |
| Total line number = 1 | |
| It costs 0.002s | |
| ``` | |
| > Note: The path of timeseries is just a filter condition, which has no relationship with the definition of level. | |
| ## Show Devices | |
| * SHOW DEVICES pathPattern? (WITH DATABASE)? devicesWhereClause? limitClause? | |
| Similar to `Show Timeseries`, IoTDB also supports two ways of viewing devices: | |
| * `SHOW DEVICES` statement presents all devices' information, which is equal to `SHOW DEVICES root.**`. | |
| * `SHOW DEVICES <PathPattern>` statement specifies the `PathPattern` and returns the devices information matching the pathPattern and under the given level. | |
| * `WHERE` condition supports `DEVICE contains 'xxx'` to do a fuzzy query based on the device name. | |
| SQL statement is as follows: | |
| ``` | |
| IoTDB> show devices | |
| IoTDB> show devices root.ln.** | |
| IoTDB> show devices root.ln.** where device contains 't' | |
| ``` | |
| You can get results below: | |
| ``` | |
| +-------------------+---------+ | |
| | devices|isAligned| | |
| +-------------------+---------+ | |
| | root.ln.wf01.wt01| false| | |
| | root.ln.wf02.wt02| false| | |
| |root.sgcc.wf03.wt01| false| | |
| | root.turbine.d1| false| | |
| +-------------------+---------+ | |
| Total line number = 4 | |
| It costs 0.002s | |
| +-----------------+---------+ | |
| | devices|isAligned| | |
| +-----------------+---------+ | |
| |root.ln.wf01.wt01| false| | |
| |root.ln.wf02.wt02| false| | |
| +-----------------+---------+ | |
| Total line number = 2 | |
| It costs 0.001s | |
| ``` | |
| `isAligned` indicates whether the timeseries under the device are aligned. | |
| To view devices' information with database, we can use `SHOW DEVICES WITH DATABASE` statement. | |
| * `SHOW DEVICES WITH DATABASE` statement presents all devices' information with their database. | |
| * `SHOW DEVICES <PathPattern> WITH DATABASE` statement specifies the `PathPattern` and returns the | |
| devices' information under the given level with their database information. | |
| SQL statement is as follows: | |
| ``` | |
| IoTDB> show devices with database | |
| IoTDB> show devices root.ln.** with database | |
| ``` | |
| You can get results below: | |
| ``` | |
| +-------------------+-------------+---------+ | |
| | devices| database|isAligned| | |
| +-------------------+-------------+---------+ | |
| | root.ln.wf01.wt01| root.ln| false| | |
| | root.ln.wf02.wt02| root.ln| false| | |
| |root.sgcc.wf03.wt01| root.sgcc| false| | |
| | root.turbine.d1| root.turbine| false| | |
| +-------------------+-------------+---------+ | |
| Total line number = 4 | |
| It costs 0.003s | |
| +-----------------+-------------+---------+ | |
| | devices| database|isAligned| | |
| +-----------------+-------------+---------+ | |
| |root.ln.wf01.wt01| root.ln| false| | |
| |root.ln.wf02.wt02| root.ln| false| | |
| +-----------------+-------------+---------+ | |
| Total line number = 2 | |
| It costs 0.001s | |
| ``` | |
| ## Count Devices | |
| * COUNT DEVICES /<PathPattern/> | |
| The above statement is used to count the number of devices. At the same time, it is allowed to specify `PathPattern` to count the number of devices matching the `PathPattern`. | |
| SQL statement is as follows: | |
| ``` | |
| IoTDB> show devices | |
| IoTDB> count devices | |
| IoTDB> count devices root.ln.** | |
| ``` | |
| You can get results below: | |
| ``` | |
| +-------------------+---------+ | |
| | devices|isAligned| | |
| +-------------------+---------+ | |
| |root.sgcc.wf03.wt03| false| | |
| | root.turbine.d1| false| | |
| | root.ln.wf02.wt02| false| | |
| | root.ln.wf01.wt01| false| | |
| +-------------------+---------+ | |
| Total line number = 4 | |
| It costs 0.024s | |
| +--------------+ | |
| |count(devices)| | |
| +--------------+ | |
| | 4| | |
| +--------------+ | |
| Total line number = 1 | |
| It costs 0.004s | |
| +--------------+ | |
| |count(devices)| | |
| +--------------+ | |
| | 2| | |
| +--------------+ | |
| Total line number = 1 | |
| It costs 0.004s | |
| ``` |