EVL

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qvd_header

Take the header of <file.qvd> and produce to standard output particular information, for example EVL data definition file or number of records.

Synopsis

syntax/qvd_header
qvd_header
  <file.qvd> --output=evd
  [--date=<format>]
  [--inline]
  [-l|--null=<string>]
  [-q|--quote=<char>]
  [-r|--record-separator=<char>]
  [-s|--field-separator=<char>]
  [--timestamp=<format>]
  [--verbose]

qvd_header
  <file.qvd> --output=(json|xml)
  [--fields]
  [--verbose]

qvd_header
  <file.qvd>
  [ --table-name | --no-of-records | --fields | --tag=<xml_tag_name> ]
  [--verbose]

qvd_header
  ( --help | --usage | --version )

Options

--no-of-records

return the value of NoOfRecords tag

--fields

provide only fields’ information

--table-name

return the value of TableName

--tag=<xml_tag_name>

return the value of <xml_tag_name>

Output Options:

--output=evd

return EVD data types definition

--output=json

return information as JSON

--output=xml

return information as XML

EVD options:

--date=<date_format>

use format argument for date data type

--inline

output EVD, XML or JSON in the inline format (for example to use EVD by other component with -d option)

-l, --null=<string>

to specify what string is used for NULL values in EVD

-q, --quote=<char>

to use a quote argument in EVD

-r, --record-separator=<char>

use sep="<char>" for last field

-s, --field-separator=<char>

use sep="<char>" for each field

--timestamp=<date_format>

use format for timestamp data type

Standard options:

--help

print this help and exit

--usage

print short usage information and exit

-v, --verbose

print to stderr info/debug messages of the component

--version

print version and exit

Examples

  1. EVD example:
    qvd_header some.qvd --output=evd --record-separator="\n" \
                        --null="" --date="%Y-%m-%d"
    

    will produce for example:

    id          int              null=""
    some_stamp  timestamp        null=""
    some_date   date("%Y-%m-%d") null=""
    value       string           null="" sep="\n"
    
  2. JSON example:
    qvd_header some.qvd --output=json --fields
    

    will produce for example:

    {
      "fields":
      [
        {
          name: "REQUEST_HOUR",
          type: "timestamp",
          format: "%Y-%m-%d"
        },
        ...
      ]
    }
    

    And:

    qvd_header some.qvd --output=json
    

    will produce for example:

    {
      "name": "Table1",
      "records": 3615,
      "fields":
      [
        {
          name: "REQUEST_HOUR",
          type: "timestamp",
          format: "%Y-%m-%d",
          "tags": [
            "$numeric",
            "$timestamp"
          ]
        },
        ...
      ]
    }