library(here) # manage file paths
library(socviz) # data and some useful functions
library(tidyverse) # your friend and mine
library(gapminder) # inescapable
library(DBI) # DBMS interface layer
library(duckdb) # Local database serverModern Plain Text Social Science
Week 09
Duke University
October 2026
Mostly in this case, datasets that are nominally larger than your laptop’s memory.
There are other more specific uses, and truly huge data is beyond the scope of the course. But we can look at methods for working with data that’s “big” for all practical purposes.
When we’re working with data in the social sciences the basic case is a single table that we’re going to do something with, like run a regression or make a plot.
# A tibble: 1,704 × 6
country continent year lifeExp pop gdpPercap
<fct> <fct> <int> <dbl> <int> <dbl>
1 Afghanistan Asia 1952 28.8 8425333 779.
2 Afghanistan Asia 1957 30.3 9240934 821.
3 Afghanistan Asia 1962 32.0 10267083 853.
4 Afghanistan Asia 1967 34.0 11537966 836.
5 Afghanistan Asia 1972 36.1 13079460 740.
6 Afghanistan Asia 1977 38.4 14880372 786.
7 Afghanistan Asia 1982 39.9 12881816 978.
8 Afghanistan Asia 1987 40.8 13867957 852.
9 Afghanistan Asia 1992 41.7 16317921 649.
10 Afghanistan Asia 1997 41.8 22227415 635.
# ℹ 1,694 more rows
But the bigger a dataset gets, the more we have to think about whether we really want (or even can have) all of it in memory all the time.
In addition, much of what we want to do with a specific dataset will involve actually acting on some relatively small subset of it.
In addition, much of what we want to do with a specific dataset will involve actually acting on some relatively small subset of it.
# A tibble: 30 × 6
country continent year lifeExp pop gdpPercap
<fct> <fct> <int> <dbl> <int> <dbl>
1 Albania Europe 1977 68.9 2509048 3533.
2 Austria Europe 1977 72.2 7568430 19749.
3 Belgium Europe 1977 72.8 9821800 19118.
4 Bosnia and Herzegovina Europe 1977 69.9 4086000 3528.
5 Bulgaria Europe 1977 70.8 8797022 7612.
6 Croatia Europe 1977 70.6 4318673 11305.
7 Czech Republic Europe 1977 70.7 10161915 14800.
8 Denmark Europe 1977 74.7 5088419 20423.
9 Finland Europe 1977 72.5 4738902 15605.
10 France Europe 1977 73.8 53165019 18293.
# ℹ 20 more rows
In addition, much of what we want to do with a specific dataset will involve actually acting, at any given moment, on some relatively small subset of it.
# A tibble: 5 × 4
continent lifeExp pop gdpPercap
<fct> <dbl> <dbl> <dbl>
1 Africa 48.9 9916003. 2194.
2 Americas 64.7 24504795. 7136.
3 Asia 60.1 77038722. 7902.
4 Europe 71.9 17169765. 14469.
5 Oceania 74.3 8874672. 18622.
Efficiently storing and querying really large quantities of data is the realm of the database and of Structured Query Languages.
As with everything in information technology there is a long and interesting story about various efforts to come up with a good theory of data storage and retrieval, and efficient algorithms for it. If you are interested, watch e.g. this lecture from a DBMS course from about twelve minutes in.
Local or remote?
On disk or in memory?
The important thing from the database admin’s point of view is that the data is stored efficiently, that we have a means of querying it, and those queries rely on some search-and-retrieval method that’s really fast.
There’s no free lunch. We want storage methods to be efficient and queries to be fast because the datasets are gonna be gigantic, and accessing them will take time.
A real database is usually not a single giant table. Instead it is more like a list of tables that are partially connected through key—i.e. columns with some values—shared between tables. Those keys are indexed and the tables are stored in a tree-like way that makes searching much faster than just going down each row and looking for matches.
From a social science perspective, putting things in different tables might be thought of a matter of logically organizing entities at different units of observation. Querying tables is a matter of assembling ad hoc tables for some chosen set of variables and at some specific unit of analysis.
(Again, “What is a row in this table?” is our most basic question.)
# A tibble: 1,704 × 8
country continent year lifeExp country_fr iso3 area_pct gm_countries
<chr> <chr> <dbl> <dbl> <chr> <chr> <dbl> <dbl>
1 Afghanistan Asia 1952 28.8 Afghanistan … AFG 29.8 33
2 Afghanistan Asia 1957 30.3 Afghanistan … AFG 29.8 33
3 Afghanistan Asia 1962 32.0 Afghanistan … AFG 29.8 33
4 Afghanistan Asia 1967 34.0 Afghanistan … AFG 29.8 33
5 Afghanistan Asia 1972 36.1 Afghanistan … AFG 29.8 33
6 Afghanistan Asia 1977 38.4 Afghanistan … AFG 29.8 33
7 Afghanistan Asia 1982 39.9 Afghanistan … AFG 29.8 33
8 Afghanistan Asia 1987 40.8 Afghanistan … AFG 29.8 33
9 Afghanistan Asia 1992 41.7 Afghanistan … AFG 29.8 33
10 Afghanistan Asia 1997 41.8 Afghanistan … AFG 29.8 33
# ℹ 1,694 more rows
In Social Science terms, redundancies are annoying in part because they apply to different levels or units of observation. From a database point of view, they are bad because they make errors or anomalies more likely when updating the table, and they make queries inefficient.
A hierarchical set of rules and criteria for ensuring the integrity of data stored across multiple tables and for reducing redundancy in data storage.
Tries to eliminate various sources of error — so-called Insertion, Update, and Deletion anomalies — particularly ones that will pollute, damage, or corrupt things beyond the specific change.
Redundancy and error are minimized by breaking the database up into a series of linked tables. Each table expresses a relation of some kind, and we can deduce new relations (i.e. new tables) by writing statements in a query language that returns tables expressing that relation, and containing the records that satisfy the relation. Hence the term “relational database”.
0NF: No duplicate rows!
1NF: Using row order to convey information is not allowed; Mixing data types in the same column is not allowed; Tables without a primary key are not allowed. Primary keys can be defined by more than one column though. No “repeating groups”.
2NF: Each non-key attribute must depend on the entire primary key
3NF: Every non-key attribute should depend wholly and only on the key.
Think of these rules in connection with ideas about “tidy data” that we’ve already covered.
# A tibble: 1,704 × 13
country continent year lifeExp pop gdpPercap area_pct pop_pct
<chr> <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 Afghanistan Asia 1952 28.8 8425333 779. 29.8 59.4
2 Afghanistan Asia 1957 30.3 9240934 821. 29.8 59.4
3 Afghanistan Asia 1962 32.0 10267083 853. 29.8 59.4
4 Afghanistan Asia 1967 34.0 11537966 836. 29.8 59.4
5 Afghanistan Asia 1972 36.1 13079460 740. 29.8 59.4
6 Afghanistan Asia 1977 38.4 14880372 786. 29.8 59.4
7 Afghanistan Asia 1982 39.9 12881816 978. 29.8 59.4
8 Afghanistan Asia 1987 40.8 13867957 852. 29.8 59.4
9 Afghanistan Asia 1992 41.7 16317921 649. 29.8 59.4
10 Afghanistan Asia 1997 41.8 22227415 635. 29.8 59.4
# ℹ 1,694 more rows
# ℹ 5 more variables: gm_countries <dbl>, country_fr <chr>, iso2 <chr>,
# iso3 <chr>, number <dbl>
# A tibble: 1,704 × 6
country continent year lifeExp pop gdpPercap
<fct> <fct> <int> <dbl> <int> <dbl>
1 Afghanistan Asia 1952 28.8 8425333 779.
2 Afghanistan Asia 1957 30.3 9240934 821.
3 Afghanistan Asia 1962 32.0 10267083 853.
4 Afghanistan Asia 1967 34.0 11537966 836.
5 Afghanistan Asia 1972 36.1 13079460 740.
6 Afghanistan Asia 1977 38.4 14880372 786.
7 Afghanistan Asia 1982 39.9 12881816 978.
8 Afghanistan Asia 1987 40.8 13867957 852.
9 Afghanistan Asia 1992 41.7 16317921 649.
10 Afghanistan Asia 1997 41.8 22227415 635.
# ℹ 1,694 more rows
# A tibble: 5 × 5
continent_id continent area_pct pop_pct gm_countries
<dbl> <chr> <dbl> <dbl> <dbl>
1 1 Africa 20.3 17.6 52
2 2 Americas 28.1 13 25
3 3 Asia 29.8 59.4 33
4 4 Europe 6.7 9.4 30
5 5 Oceania 5.7 0.6 2
# A tibble: 1,704 × 6
country continent year lifeExp pop gdpPercap
<fct> <fct> <int> <dbl> <int> <dbl>
1 Afghanistan Asia 1952 28.8 8425333 779.
2 Afghanistan Asia 1957 30.3 9240934 821.
3 Afghanistan Asia 1962 32.0 10267083 853.
4 Afghanistan Asia 1967 34.0 11537966 836.
5 Afghanistan Asia 1972 36.1 13079460 740.
6 Afghanistan Asia 1977 38.4 14880372 786.
7 Afghanistan Asia 1982 39.9 12881816 978.
8 Afghanistan Asia 1987 40.8 13867957 852.
9 Afghanistan Asia 1992 41.7 16317921 649.
10 Afghanistan Asia 1997 41.8 22227415 635.
# ℹ 1,694 more rows
# A tibble: 5 × 5
continent_id continent area_pct pop_pct gm_countries
<dbl> <chr> <dbl> <dbl> <dbl>
1 1 Africa 20.3 17.6 52
2 2 Americas 28.1 13 25
3 3 Asia 29.8 59.4 33
4 4 Europe 6.7 9.4 30
5 5 Oceania 5.7 0.6 2
# A tibble: 249 × 8
country_id continent_id country iso_country country_fr iso2 iso3 number
<dbl> <dbl> <chr> <chr> <chr> <chr> <chr> <dbl>
1 1 3 Afghanistan Afghanistan Afghanist… AF AFG 4
2 2 4 Albania Albania Albanie (… AL ALB 8
3 3 1 Algeria Algeria Algérie (… DZ DZA 12
4 4 NA <NA> American S… Samoa amé… AS ASM 16
5 5 NA <NA> Andorra Andorre (… AD AND 20
6 6 1 Angola Angola Angola (l… AO AGO 24
7 7 NA Anguilla Anguilla Anguilla AI AIA 660
8 8 NA Antarctica Antarctica Antarctiq… AQ ATA 10
9 9 NA Antigua an… Antigua an… Antigua-e… AG ATG 28
10 10 2 Argentina Argentina Argentine… AR ARG 32
# ℹ 239 more rows
# A tibble: 249 × 8
country_id continent_id country iso_country country_fr iso2 iso3 number
<dbl> <dbl> <chr> <chr> <chr> <chr> <chr> <dbl>
1 1 3 Afghanistan Afghanistan Afghanist… AF AFG 4
2 2 4 Albania Albania Albanie (… AL ALB 8
3 3 1 Algeria Algeria Algérie (… DZ DZA 12
4 4 NA <NA> American S… Samoa amé… AS ASM 16
5 5 NA <NA> Andorra Andorre (… AD AND 20
6 6 1 Angola Angola Angola (l… AO AGO 24
7 7 NA Anguilla Anguilla Anguilla AI AIA 660
8 8 NA Antarctica Antarctica Antarctiq… AQ ATA 10
9 9 NA Antigua an… Antigua an… Antigua-e… AG ATG 28
10 10 2 Argentina Argentina Argentine… AR ARG 32
# ℹ 239 more rows
# A tibble: 1,704 × 5
year country_id lifeExp pop gdpPercap
<dbl> <dbl> <dbl> <dbl> <dbl>
1 1952 1 28.8 8425333 779.
2 1957 1 30.3 9240934 821.
3 1962 1 32.0 10267083 853.
4 1967 1 34.0 11537966 836.
5 1972 1 36.1 13079460 740.
6 1977 1 38.4 14880372 786.
7 1982 1 39.9 12881816 978.
8 1987 1 40.8 13867957 852.
9 1992 1 41.7 16317921 649.
10 1997 1 41.8 22227415 635.
# ℹ 1,694 more rows
Ultimately, we query databases with SQL. There are several varieties, because there are a variety of database systems and each has their own wrinkles and quirks.
We try to abstract away from some of those quirk by using a DBI (DataBase Interface) layer, which is a generic set of commands for talking to some database. It’s analogous to an API.
We also need to use a package for the DBMS we’re talking to. It translates DBI instructions into the specific dialect the DBMS speaks.
Some databases are small, and some are far away.
Client-server databases are like websites, serving up responses to queries. The database lives on a machine somewhere in the building, or on campus or whatever.
Cloud DBMSs are like this, too, except the database lives on a machine in someone else’s building.
In-process DBMSs live and run on your laptop. We’ll use one of these, duckdb for examples here.
We need to open a connection to a database before talking to it. Conventionally this is called con.
Once connected, we ask it questions. Either we use functions or packages designed to translate our R / dplyr syntax into SQL, or we use functions to pass SQL queries on directly.
We try to minimize the amount of time we are actually making the database do a lot of work.
The key thing is that when working with databases our queries are lazy — they don’t actually do anything on the whole database unless its strictly necessary or they’re explicitly told to.
flightsHere we open a connection to an in-memory duckdb database. It’s empty. We’re going to populate it with data from nycflights.
Remember, keys and indexes are what make databases fast.
This says “go to con and get the ‘flights’ table in it, and pretend it’s a tibble called flights_db.
# A query: ?? x 19
# Database: DuckDB 1.5.5 [root@Darwin 27.0.0:R 4.6.1/:memory:]
year month day dep_time sched_dep_time dep_delay arr_time sched_arr_time
<int> <int> <int> <int> <int> <dbl> <int> <int>
1 2013 1 1 517 515 2 830 819
2 2013 1 1 533 529 4 850 830
3 2013 1 1 542 540 2 923 850
4 2013 1 1 544 545 -1 1004 1022
5 2013 1 1 554 600 -6 812 837
6 2013 1 1 554 558 -4 740 728
7 2013 1 1 555 600 -5 913 854
8 2013 1 1 557 600 -3 709 723
9 2013 1 1 557 600 -3 838 846
10 2013 1 1 558 600 -2 753 745
# ℹ more rows
# ℹ 11 more variables: arr_delay <dbl>, carrier <chr>, flight <int>,
# tailnum <chr>, origin <chr>, dest <chr>, air_time <dbl>, distance <dbl>,
# hour <dbl>, minute <dbl>, time_hour <dttm>
# A query: ?? x 5
# Database: DuckDB 1.5.5 [root@Darwin 27.0.0:R 4.6.1/:memory:]
year month day dep_delay arr_delay
<int> <int> <int> <dbl> <dbl>
1 2013 1 1 2 11
2 2013 1 1 4 20
3 2013 1 1 2 33
4 2013 1 1 -1 -18
5 2013 1 1 -6 -25
6 2013 1 1 -4 12
7 2013 1 1 -5 19
8 2013 1 1 -3 -14
9 2013 1 1 -3 -8
10 2013 1 1 -2 8
# ℹ more rows
# A query: ?? x 19
# Database: DuckDB 1.5.5 [root@Darwin 27.0.0:R 4.6.1/:memory:]
year month day dep_time sched_dep_time dep_delay arr_time sched_arr_time
<int> <int> <int> <int> <int> <dbl> <int> <int>
1 2013 1 1 848 1835 853 1001 1950
2 2013 1 1 1815 1325 290 2120 1542
3 2013 1 1 1842 1422 260 1958 1535
4 2013 1 1 2115 1700 255 2330 1920
5 2013 1 1 2205 1720 285 46 2040
6 2013 1 1 2343 1724 379 314 1938
7 2013 1 2 1332 904 268 1616 1128
8 2013 1 2 1412 838 334 1710 1147
9 2013 1 2 1607 1030 337 2003 1355
10 2013 1 2 2131 1512 379 2340 1741
# ℹ more rows
# ℹ 11 more variables: arr_delay <dbl>, carrier <chr>, flight <int>,
# tailnum <chr>, origin <chr>, dest <chr>, air_time <dbl>, distance <dbl>,
# hour <dbl>, minute <dbl>, time_hour <dttm>
# A query: ?? x 2
# Database: DuckDB 1.5.5 [root@Darwin 27.0.0:R 4.6.1/:memory:]
dest mean_dep_delay
<chr> <dbl>
1 HOU 14.3
2 PHX 10.4
3 SYR 14.4
4 BDL 17.7
5 BWI 16.4
6 SAT 20.7
7 PSP -2.94
8 SFO 12.9
9 GSP 19.3
10 TYS 28.5
# ℹ more rows
This doesn’t touch the database.
Even when we ask to look at it, it just does the absolute minimum required.
# A query: ?? x 4
# Database: DuckDB 1.5.5 [root@Darwin 27.0.0:R 4.6.1/:memory:]
# Ordered by: desc(mean_arr_delay)
tailnum mean_dep_delay mean_arr_delay n
<chr> <dbl> <dbl> <dbl>
1 N11119 32.6 30.3 148
2 N16919 32.4 29.9 251
3 N14998 29.4 27.9 230
4 N15910 29.3 27.6 280
5 N13123 29.6 26.0 121
6 N11192 27.5 25.9 154
7 N14950 26.2 25.3 219
8 N21130 27.0 25.0 126
9 N24128 24.8 24.9 129
10 N22971 26.5 24.7 230
# ℹ more rows
collect()# A tibble: 1,201 × 4
tailnum mean_dep_delay mean_arr_delay n
<chr> <dbl> <dbl> <dbl>
1 N11119 32.6 30.3 148
2 N16919 32.4 29.9 251
3 N14998 29.4 27.9 230
4 N15910 29.3 27.6 280
5 N13123 29.6 26.0 121
6 N11192 27.5 25.9 154
7 N14950 26.2 25.3 219
8 N21130 27.0 25.0 126
9 N24128 24.8 24.9 129
10 N22971 26.5 24.7 230
# ℹ 1,191 more rows
Now it exists for realsies.
Database systems will have more than one table. We query and join them. The idea is that getting the DBMS to do this will be way faster and more memory-efficient than trying to get dplyr to do it.
[1] "flights" "planes"
See what we did there? It’s like con the database connection has a list of tables in it.
# A query: ?? x 11
# Database: DuckDB 1.5.5 [root@Darwin 27.0.0:R 4.6.1/:memory:]
year month day dep_time arr_time carrier flight tailnum year_built type
<int> <int> <int> <int> <int> <chr> <int> <chr> <int> <chr>
1 2013 1 1 517 830 UA 1545 N14228 1999 Fixed …
2 2013 1 1 533 850 UA 1714 N24211 1998 Fixed …
3 2013 1 1 542 923 AA 1141 N619AA 1990 Fixed …
4 2013 1 1 544 1004 B6 725 N804JB 2012 Fixed …
5 2013 1 1 554 812 DL 461 N668DN 1991 Fixed …
6 2013 1 1 554 740 UA 1696 N39463 2012 Fixed …
7 2013 1 1 555 913 B6 507 N516JB 2000 Fixed …
8 2013 1 1 557 709 EV 5708 N829AS 1998 Fixed …
9 2013 1 1 557 838 B6 79 N593JB 2004 Fixed …
10 2013 1 1 558 849 B6 49 N793JB 2011 Fixed …
# ℹ more rows
# ℹ 1 more variable: model <chr>
Close your connection!
I’m not going to do it on the slides. We’ll do it live. We will process a pretty big data file on a machine of modest proportions.