Opal management

Opal management

Logging onto the Opal management interface

  • If using the cloud training environment your trainer will have switched the training Opal servers on.

  • If using local VMs Start the Opal servers 

Starting the Opal training VMs

Having opened the training Opal VMs, it is necessary to leave them running for a couple of minutes before trying to login. If you do not wait long enough you will find

  • you may not be given the login window or 

  • after entering username and password the window just hangs

When the training Opal servers are ready the login window appears very rapidly. Once you have entered the user name and password the Opal web interface appears almost immediately. 

  • Your opal servers will sit at an IP address on port :8080 (http) or :8443 (https)

DataSHIELD Training Environment

Description

IP Address

DataSHIELD Training Environment

Description

IP Address

VMs

DataSHIELD training Opal on your local machine

http://192.168.56.100:8080

http://192.168.56.101:8080

Cloud

DataSHIELD training Opal in the cloud

Ask your trainer.

  • Navigate to the address in your web browser 

  • Enter the username and password - default training details given below

Training Environment

Default Username

Default Password

Training Environment

Default Username

Default Password

VMs

administrator

datashield_test&

Cloud

administrator

datashield_test&

Managing data in Opal

Simulated datasets are provided in the training Opal servers. However, users may wish to conduct analysis on their own simulated data. The instructions on this page will allow you to upload your own simulated data to your training Opal servers. You can split one simulated dataset into two - and upload half the dataset onto one Opal server and the rest on the second server.

Preparing your data for Opal

Opal servers require that a formal data dictionary is specified and uploaded in order that a data set can be properly imported.

Opal accepts various formats but in this tutorial a .csv is used for the data file and Microsoft Excel for the data dictionary file (.xls or .xlsx).  

The data dictionary file

  • Download the sample dataset alspacsim.csv or use your own data table in .csv format. This is a simulated dataset from the ALSPAC clinic at participant age 7.

Variable name

Description

Categorical

Variable name

Description

Categorical

MALE

codes sex

1 = male

0 = female

AGE_YEARS

age in decimal years on the day of the clinic



HEIGHT

height age 7 (cm)



HEIGHT_SIT

sitting height age 7 (cm)



WAIST

waist circumference age 7 (cm)



HIP

hip circumference age 7 (cm)



WEIGHT

weight age 7 (Kg)



SBP

systolic blood pressure age 7 (top of the blood pressure fluctuation) (mm of Hg)



DPB

diastolic blood pressure age 7 (bottom of the blood pressure fluctuation) (mm of Hg)



PULSE

pulse rate age 7 (beats per minute)



BMI

Body Mass Index derived as wt/(ht/100)2 The height variable is divided by 100
to express it in metres rather than centimeters



  • Download the Opal-dictionary-template.xls template. You will need to follow the instructions below to compile a data dictionary for the new dataset in order to upload it to Opal.

  • The data dictionary file requires formatting as an Excel spreadsheet (.xls or .xlsx) with two tabs Variables and Categories.

The variables tab

The image below shows the variables tab for the simulated dataset CNSIM used within the v4 Tutorial for DataSHIELD users.

The table below summarises the column names in the variables tab, including examples from the test data built into the training environment in the spreadsheet image above.

Column Names

Description

Default value

Example value in the test data

Notes

Column Names

Description

Default value

Example value in the test data

Notes

table

the table name the variable will be added to

Table

Column A (CNSIM)

This is the table name you refer to in your DataSHIELD login details.

It is critical that the table name appears in every row

name

the variable name



Column B (e.g. LAB_TSC)

Mandatory field.
Becomes the the column name in Opal for that variable

valueType

the value type of the variable

text

Column C (e.g. decimal, integer)

See further information on variable types and classes

entityType

Opal can store data on different entities

Participant

Column D (e.g. Participant)

Examples: Participant (each row corresponds to a different participant), Instrument, Area, Drug

referencedEntityType

if the variable values are entity identifiers, this is the type of the entities that are referenced



Column E

Can be left blank

mimeType

the mime type of the variable to help applications to display documents



Column F

Examples: image/jpeg, application/excel. Can be left blank

unit

the unit in which variables are expressed



Column G (e.g. Participant)

Examples: cm, kg, ml etc. Can be left blank

repeatable

repeatable measurements

0

Column H (0)

1 if repeatable, 0 if not (e.g. Three measures of blood pressure)

occurrenceGroup

name of a repeatable variable group



Column I

Example: [measure value, measure date] is a group of variables that can be repeated. Can be left blank

label:en

label of the variable.



Column J

Can be localized by language e.g. label:en in english, label:fr for french)

alias

Alternative name for the variable, usually used for defining a shorter name for the variable



Column K



  • Edit the variable tab of your data dictionary template to reflect the variables in alspacsim.csv (or your own data). 

The categories tab

The image below shows the categories tab for the simulated dataset CNSIM used within the v4 Tutorial for DataSHIELD users.  Each category for each variable is represented by a single row in the spreadsheet.  For example, in the dictionary file below, 3 rows (rows 12-14 inclusive) are for PM_BMI_CATEGORICAL as it has 3 categories.

The table below summarises the column names in the categories tab, including examples from the simulated datasets built into the DataSHIELD training environments in the spreadsheet image above.

Column Names

Description

Default value

Example value in the test data

Notes

Column Names

Description

Default value

Example value in the test data

Notes

table

the table name the variable will be added to

Table

Column A (CNSIM)

This is the table name you refer to in your DataSHIELD login details.

It is critical that the table name appears in every row

variable

the variable name (mandatory field)



Column B (e.g. DIS_CVA)

mandatory field. One row per category for each variable.

name

the variable category

integer

Column C (e.g. 1)

mandatory field. One row per category for each variable

code

can be left blank



Column D

Can be left blank

missing

Some categories are interpreted as missing answers (e.g. 'Don't know', 'Prefer not to answer').  

0

Column E

Use 1 for missing and 0 for not missing (normal answer).

label:en

label of the variable category



Column F

Human readable text description of the category. Can be localized by language e.g. label:en in english, label:fr for french)

  • Edit the categories tab of your data dictionary template to reflect the variables in alspacsim.csv (or your own data). 

The data file

  • In the training Opal servers, the data file is a .csv (comma delimited) file

  • Missing values are represented in the data file as two consecutive commas ,,

Missing values

Missing values can not be represented as white space or NA

  • There is no column name for the first column.  The first column contains the row number for the data. "Participant" or Opal ID number setting in Opal is using the row number. 

  • See below for an example of what the .csv file looks like when opened in Excel.

Uploading your data and data dictionary files to Opal

Data structure in Opal

Data are held in Opal in what is called a table.

  • each row contains the data for one of the primary units of data collection (perhaps most commonly, a participant)

  • each column represents a different variable.

Opal holds all relevant data tables in a project.

Creating a new Opal project

The first step to uploading your data to Opal is to indicate within which project you want to site the new data table. This may either be an existing project or a new one:

  • To create a new project click on the Project tab in the top left (after clicking it appears in green on the dark blue horizontal bar) 

  •  click Add Project.

Fill in the details of your project:

  • You must specify a name and this will be used to point to the data. For convenience do not use a very long name. The example below shows the name as CNSIM.

  • The "title" can then be a longer explanatory label for the table

  • The database currently defaults to mongodb but can also be MySQL

  • You can give an additional description if you wish

Project and table names

In DataSHIELD in order to refer uniquely to a table held in Opal you must specify both the Opal project and table names. For example the table EMISS in the SURVSIM Project is referred to as SURVSIM.EMISS in your DataSHIELD login template. In the case of the training data, it happens to be that both the Project and the Table within it are called CNSIM - and so the table is referred to as CNSIM.CNSIM.

Upload data and data dictionary into Opal 

To make data available in Opal, you need to upload the data dictionary (.xls) and the data (.csv) files you have created:

  • To upload data files from your local computer,  click on Dashboard from the top menu bar (the word changes to green)

  • Click Manage Files from the left hand menu

  • By default, you will see a list of files currently held in your Opal Home folder. This is where your dictionary and data files will be saved.  

If you want to save the data in a project-specific directory (which is often recommended) then click Projects from the left hand menu and choose the project you will be working in.

You can also create a new folder by navigating to wherever you want the new folder to be (e.g. you may want to navigate to the Project folder and then create a new subfolder within that Project folder). Once you are there click Add Folder (button with blue background on top left) and specify the name of the new folder. 

If, when you have finalised where you want to keep the data, you find that the .xls and/or .csv file already exist in that location, you need to decide whether the pre-existing files are current or whether you need to over-write them with the up-to-date version(s). Rather than making a default assumption about this, Opal explicitly asks you what decision you would like to take.

To upload the data dictionary (.xls file) and the data file (.csv file):

  • Click the grey Upload button from the top tab

  • This brings up a new window, click Choose file

  • Browse to the .xls file to upload from your your local machine 

  • Select that file and click open (you can simply double-click the file in Windows)

  • Clicking the dark blue upload at the bottom of the window

  • If that file already exists in that location then it will ask you whether to replace it or not (see above tip)

  • Repeat for the .csv (data file)

Creating the Opal table: the data dictionary 

Your data dictionary (.xls) and data (.csv) files should now be uploaded into Opal. However, at present they simply exist as stored files, the data cannot be used in Opal until you have converted them into an Opal data table.

  • Click on the Projects tab from the top menu (it will turn green) and click on your project name (CNSIM in the example below)

  • Click on the large blue +Add Table button that sits  above the list of tables in the project you have specified

  • Select Add/update tables from dictionary ... from the drop down menu

  • Use HOMES and SYSTEM on your left menu to navigate to the folder that holds the .xls data dictionary file

  • Click the small square box to the left of the file name (a tick appears) and then click the dark blue Select button towards the bottom right

  • Click the blue Next button

  • Review the Opal table in the pop up window. If this is a new data table the information in the window should tell you the name of the Table you have asked to be created and the number of New Variables (corresponding to number of columns in your .csv data file).

The table name must match the first column of the two tabs in the .xls data dictionary file.

  • If the information is correct, click the small box to the left of the table name (CNSIM in the example below). A tick will appear. 

  • Click the dark blue Finish button from the bottom right

  • This will take you back to the list of all available tables in the chosen project, and after a few seconds this will be refreshed to include the new table you have create

Creating the Opal table: the data

  • Select your project again by clicking on the Projects tab from the top menu and click on your project name (CNSIM in this particular example)

  • Your table states as holding 0 Entities (indicating it is empty)

  • Click on the small box at the left of the table name, and a tick will appear.

  • Click the grey Import button from the tabs above the table.  This opens a window to define file format.

  • The data file is a .csv file. By default the window should state CSV. If it does not, choose CSV fromthe drop down menu.

  • Now click the blue Next button to open the Import Data window.

  • Specify data file location by selecting the grey Browse button. Use the left menu to navigate to the folder that holds the required file.

  • Click the small square box to the left of the file name (a tick appears) and then click the dark blue Select button on the bottom right

  • Destination Table: type the data table name.  This needs to be the same name as your Opal data dictionary table, in this example CNSIM. 

As soon as you start typing the table name, Opal will list you all of the valid Opal tables it currently holds, you only have to click on the correct one rather than typing the whole name.

  • Entity Type:  This is the observational unit that contributes each row in the .csv data file and will be the same as in column D under the Variables tab in the data dictionary .xls file.  The default is Participant

You can use Entity Type: Participant in the data dictionary column D even if, as in some survival models, each row in the data set corresponds to something other than a single participant.

  • Click the blue Next> button to open up the Configure Data Import window which you can ignore. 

  • Click the blue Next> button to open up the Review and select the data dictionaries you wish to import window. 

  • Select the box for the correct Table into which Opal will import the data.  A tick will appear.

  • Then click the blue Next> button to open up the Review the data that will be imported window .  This shows you the first few rows and columns of the data in the .csv file you selected to read in. 

You can navigate the review data table by clicking the green < and > buttons on the header line. If you want to go down or up the file looking for rows below or above what you can see, use the white on grey DVD-like buttons above the table. If you hover the cursor over each button an explanation will appear.

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