About
The data head command print only the N first records of a data resource.
This command is useful to print content of data resource that have a big size.
To print a data resource, you can also use:
- the print command to print the whole content of a data resource
- the tail command to print the last content of a data resource
Syntax
tabli data head -h
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.