diff --git a/README.md b/README.md
index eeef632..6086f06 100644
--- a/README.md
+++ b/README.md
@@ -48,3 +48,39 @@ end
 
 * `Time` is implemented as `TEXT` column using `SQLite3::DATE_FORMAT_SUBSECOND` format (or `SQLite3::DATE_FORMAT_SECOND` if the text does not contain a dot).
 * `Bool` is implemented as `INT` column mapping `0`/`1` values.
+
+### Setting PRAGMAs
+
+You can adjust certain [SQLite3 PRAGMAs](https://www.sqlite.org/pragma.html)
+automatically when the connection is created by using the query parameters:
+
+```crystal
+require "sqlite3"
+
+DB.open "sqlite3://./data.db?_journal_mode=wal&_synchronous=normal" do |db|
+  # this database now uses WAL journal and normal synchronous mode
+  # (defaults were `delete` and `full`, respectively)
+end
+```
+
+The following is the list of supported options:
+
+| Name                      | Connection key  |
+|---------------------------|-----------------|
+| [Busy Timeout][pragma-to] | `_busy_timeout` |
+| [Cache Size][pragma-cs] | `_cache_size` |
+| [Foreign Keys][pragma-fk] | `_foreign_keys` |
+| [Journal Mode][pragma-jm] | `_journal_mode` |
+| [Synchronous][pragma-sync] | `_synchronous` |
+| [WAL autocheckoint][pragma-walck] | `_wal_autocheckpoint` |
+
+Please note there values passed using these connection keys are passed
+directly to SQLite3 without check or evaluation. Using incorrect values result
+in no error by the library.
+
+[pragma-to]: https://www.sqlite.org/pragma.html#pragma_busy_timeout
+[pragma-cs]: https://www.sqlite.org/pragma.html#pragma_cache_size
+[pragma-fk]: https://www.sqlite.org/pragma.html#pragma_foreign_keys
+[pragma-jm]: https://www.sqlite.org/pragma.html#pragma_journal_mode
+[pragma-sync]: https://www.sqlite.org/pragma.html#pragma_synchronous
+[pragma-walck]: https://www.sqlite.org/pragma.html#pragma_wal_autocheckpoint
diff --git a/spec/connection_spec.cr b/spec/connection_spec.cr
index be3bf0c..0eabc13 100644
--- a/spec/connection_spec.cr
+++ b/spec/connection_spec.cr
@@ -10,6 +10,14 @@ private def dump(source, target)
   end
 end
 
+private def it_sets_pragma_on_connection(pragma : String, option : String, value : String, expected, file = __FILE__, line = __LINE__)
+  it "sets pragma '#{pragma}' to #{expected} using '#{option}'", file, line do
+    with_db("#{DB_FILENAME}?#{option}=#{value}") do |db|
+      db.scalar("PRAGMA #{pragma}").should eq(expected)
+    end
+  end
+end
+
 describe Connection do
   it "opens a database and then backs it up to another db" do
     with_db do |db|
@@ -68,4 +76,34 @@ describe Connection do
       cnn.scalar("select count(*) from person").should eq(1)
     end
   end
+
+  # adjust busy_timeout pragma (default is 0)
+  it_sets_pragma_on_connection "busy_timeout", "_busy_timeout", "1000", 1000
+
+  # adjust cache_size pragma (default is -2000, 2MB)
+  it_sets_pragma_on_connection "cache_size", "_cache_size", "-4000", -4000
+
+  # enable foreign_keys, no need to test off (is the default)
+  it_sets_pragma_on_connection "foreign_keys", "_foreign_keys", "1", 1
+  it_sets_pragma_on_connection "foreign_keys", "_foreign_keys", "yes", 1
+  it_sets_pragma_on_connection "foreign_keys", "_foreign_keys", "true", 1
+  it_sets_pragma_on_connection "foreign_keys", "_foreign_keys", "on", 1
+
+  # change journal_mode (default is delete)
+  it_sets_pragma_on_connection "journal_mode", "_journal_mode", "delete", "delete"
+  it_sets_pragma_on_connection "journal_mode", "_journal_mode", "truncate", "truncate"
+  it_sets_pragma_on_connection "journal_mode", "_journal_mode", "persist", "persist"
+
+  # change synchronous mode (default is 2, FULL)
+  it_sets_pragma_on_connection "synchronous", "_synchronous", "0", 0
+  it_sets_pragma_on_connection "synchronous", "_synchronous", "off", 0
+  it_sets_pragma_on_connection "synchronous", "_synchronous", "1", 1
+  it_sets_pragma_on_connection "synchronous", "_synchronous", "normal", 1
+  it_sets_pragma_on_connection "synchronous", "_synchronous", "2", 2
+  it_sets_pragma_on_connection "synchronous", "_synchronous", "full", 2
+  it_sets_pragma_on_connection "synchronous", "_synchronous", "3", 3
+  it_sets_pragma_on_connection "synchronous", "_synchronous", "extra", 3
+
+  # change wal_autocheckpoint (default is 1000)
+  it_sets_pragma_on_connection "wal_autocheckpoint", "_wal_autocheckpoint", "0", 0
 end
diff --git a/src/sqlite3/connection.cr b/src/sqlite3/connection.cr
index ca60043..ec07224 100644
--- a/src/sqlite3/connection.cr
+++ b/src/sqlite3/connection.cr
@@ -2,10 +2,11 @@ class SQLite3::Connection < DB::Connection
   def initialize(database)
     super
     filename = self.class.filename(database.uri)
-    # TODO maybe enable Flag::URI to parse query string in the uri as additional flags
     check LibSQLite3.open_v2(filename, out @db, (Flag::READWRITE | Flag::CREATE), nil)
     # 2 means 2 arguments; 1 is the code for UTF-8
     check LibSQLite3.create_function(@db, "regexp", 2, 1, nil, SQLite3::REGEXP_FN, nil, nil)
+
+    process_query_params(database.uri)
   rescue
     raise DB::ConnectionRefused.new
   end
@@ -88,4 +89,36 @@ class SQLite3::Connection < DB::Connection
   private def check(code)
     raise Exception.new(self) unless code == 0
   end
+
+  private def process_query_params(uri : URI)
+    return unless query = uri.query
+
+    pragmas = Hash(String, String).new
+
+    URI::Params.parse(query) do |key, value|
+      case key
+      when "_busy_timeout"
+        pragmas["busy_timeout"] = value
+      when "_cache_size"
+        pragmas["cache_size"] = value
+      when "_foreign_keys"
+        pragmas["foreign_keys"] = value
+      when "_journal_mode"
+        pragmas["journal_mode"] = value
+      when "_synchronous"
+        pragmas["synchronous"] = value
+      when "_wal_autocheckpoint"
+        pragmas["wal_autocheckpoint"] = value
+      end
+    end
+
+    # concatenate all into a single SQL string
+    sql = String.build do |str|
+      pragmas.each do |key, value|
+        str << "PRAGMA #{key}=#{value};"
+      end
+    end
+
+    check LibSQLite3.exec(@db, sql, nil, nil, nil)
+  end
 end
diff --git a/src/sqlite3/lib_sqlite3.cr b/src/sqlite3/lib_sqlite3.cr
index 9455f8b..310e69c 100644
--- a/src/sqlite3/lib_sqlite3.cr
+++ b/src/sqlite3/lib_sqlite3.cr
@@ -86,6 +86,7 @@ lib LibSQLite3
   fun backup_finish = sqlite3_backup_finish(SQLite3Backup) : Code
 
   fun prepare_v2 = sqlite3_prepare_v2(db : SQLite3, zSql : UInt8*, nByte : Int32, ppStmt : Statement*, pzTail : UInt8**) : Int32
+  fun exec = sqlite3_exec(db : SQLite3, zSql : UInt8*, pCallback : Callback, pCallbackArgs : Void*, pzErrMsg : UInt8**) : Int32
   fun step = sqlite3_step(stmt : Statement) : Int32
   fun column_count = sqlite3_column_count(stmt : Statement) : Int32
   fun column_type = sqlite3_column_type(stmt : Statement, iCol : Int32) : ::SQLite3::Type