====== Tabli - Data Head Command ======


===== About =====
The ''data head'' command [[print|print]] only the ''N'' first records of a [[docs:resource:resource|data resource]].

This command is useful to print content of [[docs:resource:resource|data resource]] that have a big [[docs:resource:size|size]].

<note tip>
To print a data resource, you can also use:
  * the [[print|print command]] to print the whole content of a data resource
  * the [[tail|tail command]] to print the last content of a data resource
</note>


===== Syntax =====

<unit>
<code dos>
tabli data head -h
</code>
<console>
Tabli data head
===============

Print the first N rows of content of data resources.

By default, there is a limit of 10 on the number of rows printed



Examples
--------

 1 - Show the first 10 records of the table `sales` from the data store `sqlite`:


        tabli data head sales@sqlite


 2 - Show the first 500 rows of the table `time` from the data store `postgres`:


        tabli data head --limit 500 time@postgres


 3 - Show the first 10 lines from the file `request.log`:


        tabli data head request.log




Syntax
------


    tabli data head [options|flags] <data-selector...>


where:


  Arguments:

    <data-selector...>                                      One or more data or script selectors


  Data Definition Options:

    -a,--attribute <attributeName=value>                    Set specific data resource attributes


  Options:

    --limit <value>                                         Limit the number of rows printed (See footer)


  Selection Options:

    -wd,--with-dependencies                                 If set, the dependencies will be also selected


  Global Options:

    -cf,--conf <path>                                       The path to a configuration file

    -cv,--connection-vault <path>                           The path where the connection vault is located

    -h,--help                                               Print this help

    -l,--log-level <error|warning|tip|info|fine>            Set the log level

    -ns,--not-strict                                        A minor error will not stop the process.

    -odu,--output-data-uri <outputDataUri>                  defines the output data uri for the feedback data (default: console)

    -oo,--output-operation <dataOperation>                  defines the data operations (replace, truncate) on an existing output resource before transfer.

    -oop,--output-transfer-operation <transferOperation>    defines the output transfer operation (insert, update, merge, copy). Default to `copy` for a file system and `insert` for a database.

    -pp,--passphrase <passphrase>                           A passphrase (master password) to decrypt the encrypted values




Footer
------


Important:
We don't recommend to increase the rows limit to a very high number.
This command loads the data into memory to calculate the data layout and
render data aligned properly.
Increasing the limit will then increase the memory footprint and may cause an out-of-memory error.
</console>
</unit>