crystal-sqlite3

SQLite3 bindings for Crystal.

Check crystal-db for general db driver documentation. crystal-sqlite3 driver is registered under sqlite3:// uri.

Installation

Add this to your application's shard.yml:

dependencies:
  sqlite3:
    github: crystal-lang/crystal-sqlite3

Usage

require "sqlite3"

DB.open "sqlite3://./data.db" do |db|
  db.exec "create table contacts (name text, age integer)"
  db.exec "insert into contacts values (?, ?)", "John Doe", 30

  args = [] of DB::Any
  args << "Sarah"
  args << 33
  db.exec "insert into contacts values (?, ?)", args: args

  puts "max age:"
  puts db.scalar "select max(age) from contacts" # => 33

  puts "contacts:"
  db.query "select name, age from contacts order by age desc" do |rs|
    puts "#{rs.column_name(0)} (#{rs.column_name(1)})"
    # => name (age)
    rs.each do
      puts "#{rs.read(String)} (#{rs.read(Int32)})"
      # => Sarah (33)
      # => John Doe (30)
    end
  end

  contacts = db.query_all "SELECT name, age FROM contacts", as: {name: String, age: Int64}
  puts contacts # => [{name: "John Doe", age: 30}, {name: "Sarah", age: 33}]
end

DB::Any

• 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 automatically when the connection is created by using the query parameters:

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.

Guides

• Compile and link SQLite