Node Management

    Example：

    • return the child paths of root.ln：show child paths root.ln
    2. | child paths|
    3. +------------+
    4. |root.ln.wf01|
    5. |root.ln.wf02|
    6. +------------+
    7. Total line number = 2
    8. It costs 0.002s
    1. SHOW CHILD NODES pathPattern

    Return all child nodes of the pathPattern.

    Example：

    • return the child nodes of root：show child nodes root
    • return the child nodes of root.ln：show child nodes root.ln
    1. +------------+
    2. | child nodes|
    3. +------------+
    4. |        wf01|
    5. |        wf02|
    6. +------------+
    1. IoTDB > COUNT NODES root.** LEVEL=2
    2. IoTDB > COUNT NODES root.ln.wf01.** LEVEL=3
    3. IoTDB > COUNT NODES root.**.temperature LEVEL=3

    As for the above mentioned example and Metadata tree, you can get following results:

    Note: The path of timeseries is just a filter condition, which has no relationship with the definition of level.

    • SHOW DEVICES pathPattern? (WITH STORAGE GROUP)? limitClause? #showDevices

    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.**.
    • statement specifies the PathPattern and returns the devices information matching the pathPattern and under the given level.

    SQL statement is as follows:

    1. IoTDB> show devices
    2. IoTDB> show devices root.ln.**
    1. +-------------------+---------+
    2. |            devices|isAligned|
    3. +-------------------+---------+
    4. |  root.ln.wf01.wt01|    false|
    5. |  root.ln.wf02.wt02|    false|
    6. |root.sgcc.wf03.wt01|    false|
    7. |    root.turbine.d1|    false|
    8. +-------------------+---------+
    9. Total line number = 4
    10. It costs 0.002s
    12. +-----------------+---------+
    13. |          devices|isAligned|
    14. +-----------------+---------+
    15. |root.ln.wf01.wt01|    false|
    16. |root.ln.wf02.wt02|    false|
    17. Total line number = 2
    18. It costs 0.001s

    indicates whether the timeseries under the device are aligned.

    To view devices’ information with storage group, we can use SHOW DEVICES WITH STORAGE GROUP statement.

    • SHOW DEVICES WITH STORAGE GROUP statement presents all devices’ information with their storage group.
    • SHOW DEVICES <PathPattern> WITH STORAGE GROUP statement specifies the PathPattern and returns the devices’ information under the given level with their storage group information.

    SQL statement is as follows:

    You can get results below:

    1. +-------------------+-------------+---------+
    2. |            devices|storage group|isAligned|
    3. +-------------------+-------------+---------+
    4. |  root.ln.wf01.wt01|      root.ln|    false|
    5. |  root.ln.wf02.wt02|      root.ln|    false|
    6. |root.sgcc.wf03.wt01|    root.sgcc|    false|
    7. |    root.turbine.d1| root.turbine|    false|
    8. +-------------------+-------------+---------+
    9. Total line number = 4
    10. It costs 0.003s
    12. +-----------------+-------------+---------+
    13. |          devices|storage group|isAligned|
    14. +-----------------+-------------+---------+
    15. |root.ln.wf01.wt01|      root.ln|    false|
    16. |root.ln.wf02.wt02|      root.ln|    false|
    17. +-----------------+-------------+---------+
    18. Total line number = 2