diff --git a/mysql.nix b/mysql.nix
index 1a49154..dd1a266 100644
--- a/mysql.nix
+++ b/mysql.nix
@@ -21,7 +21,9 @@ in mkShell {
     mysqld --datadir="${data_dir}" --socket="${socket}" --skip-networking --skip-mysqlx &
     sleep 1
 
-    mysql --socket="${socket}" -u root < ${sql_file}
+    if [ ! -d ${data_dir} ]; then
+      mysql --socket="${socket}" -u root < ${sql_file}
+    fi
 
     alias mysql='mysql --socket="${socket}" -u root'
     alias nuke='rm -rf ${data_dir}'
diff --git a/postgresql.nix b/postgresql.nix
index aec4a61..02bbed1 100644
--- a/postgresql.nix
+++ b/postgresql.nix
@@ -22,7 +22,10 @@ in mkShell {
       pg_ctl start -o "--unix_socket_directories=${data_dir} --listen_addresses='''"
     fi
 
-    psql -d postgres -f ${sql_file}
+    if [ ! -d ${data_dir} ]; then
+      psql -d postgres -f ${sql_file}
+    fi
+
     alias psql='psql -d postgres'
     alias nuke='rm -rf ${data_dir}'
   '';