This vignette assumes that you have already been able to set up the connection to a Moodle Database and created a local cache (if chosen).

Data access functions

Learning analytics practitioners working with LMS data will often be interested in a sub-set of the available tables with relevant references added. These can be accessed through several mdl_* functions which will connect to the relevant table(s) and return a reference to the data. Currently the package supports curated access through the following functions:

For example:

my_grades <- mdl_grades()

creates an R object named my_grades containing the dbplyr reference to the table in question.

Summary functions

The R generic summary function is implemented with sensible defaults so that:

#> ----------
#> # of Grades:      1.4M 
#> Missing:      945.2K 
#> Courses:      2.8K 
#> Users:        22.9K 
#> Normalized Grades:     
#> Median:       0.967 
#> Mean:         0.859 
#> SD:           0.336

provides useful information for the learning analytics practitioner.

Plot functions

Generic plot functions are also provided for all data-access objects:


The plot functions return a ggplot by default. If you prefer base graphics you can call the function thus:

plot(my_grades, use_base_graphics = TRUE)

Additional columns

For convenience some additional columns have been added to the tables. These are all snake_case and are thus easy to spot:

my_grades %>% 
  select(contains("_")) %>% 
#> [1] "grade_id"      "activity_id"   "activity_name" "item_type"

Objects of class dbplyr

The return value from the data-access functions are also dbplyr tables so dbplyr verbs and operation work on them as well. For example:

my_grades %>% 
  filter(courseid == 4957) %>% 
#> ----------
#> # of Grades:      99 
#> Missing:      27 
#> Courses:      1 
#> Users:        11 
#> Normalized Grades:     
#> Median:       0.956 
#> Mean:         0.950 
#> SD:           0.043
my_grades %>% 
  filter(courseid == 4957) %>% 

Using ggplot objects

Since the return value of a plot function is a ggplot object it is of course possible to add and/or manipulate the plot using the syntax from the ggplot2 package. For example by annotating the plot:

my_plot <- mdl_grades() %>% 
my_plot +
  annotate("text",.45,10^5, label="Passing Grade",cex=5)+
  annotate("segment",x=.6,y=10^5,xend=.6,yend=0, lty=2)