06-Relational Database: Clarify wording and code (specific cases)

[DanielleQuinn]

There are a few places that could use a better description of the code being run:

• line 79
  results <- dbSendQuery(mydb, "SELECT * FROM Question1")

• lines 156-165
  dbfile_new = "a_newdb.sqlite"
  mydb_new = dbConnect(dbDriver("SQLite"), dbfile_new)

dbWriteTable(conn = mydb_new , name = "SN7577", value = "SN7577.csv",
row.names = FALSE, header = TRUE)

dbWriteTable(conn = mydb_new , name = "Q1", value = Q1,
row.names = FALSE)

dbListTables(mydb_new)

• line 180
  tbl(mydb_dplyr, sql("SELECT count(*) from SN7577"))

Add details re: line 104 - why should the connection be closed? Does it need to be reopened to run code in following chunks?
"Once you have retrieved the data you should close the connection."

Clarify lines 177 and 202 - unsure what they are trying to say
"as is the mthod for running queries. However using the 'tbl' functionwe still need to provide avalid SQL string."
"Notice that on the nrow command we get NA rather than a count of rows. Thisis because dplyr doesn't hold the full table even after the 'Select * ...' "

[fmichonneau]

this will need to be revisited once the database episode is brought back in. Related to #51

[kelseygonzalez]

Status update: This will be reviewed once the database episode is brought back in, pending official release of the DC Social Science SQL lesson.

[juanfung]

Closing until database episode is revived