87 lines
2.8 KiB
Markdown
87 lines
2.8 KiB
Markdown
# crystal-sqlite3 [](https://travis-ci.org/crystal-lang/crystal-sqlite3)
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SQLite3 bindings for [Crystal](http://crystal-lang.org/).
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Check [crystal-db](https://github.com/crystal-lang/crystal-db) for general db driver documentation. crystal-sqlite3 driver is registered under `sqlite3://` uri.
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## Installation
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Add this to your application's `shard.yml`:
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```yml
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dependencies:
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sqlite3:
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github: crystal-lang/crystal-sqlite3
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```
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### Usage
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```crystal
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require "sqlite3"
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DB.open "sqlite3://./data.db" do |db|
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db.exec "create table contacts (name text, age integer)"
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db.exec "insert into contacts values (?, ?)", "John Doe", 30
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args = [] of DB::Any
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args << "Sarah"
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args << 33
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db.exec "insert into contacts values (?, ?)", args: args
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puts "max age:"
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puts db.scalar "select max(age) from contacts" # => 33
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puts "contacts:"
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db.query "select name, age from contacts order by age desc" do |rs|
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puts "#{rs.column_name(0)} (#{rs.column_name(1)})"
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# => name (age)
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rs.each do
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puts "#{rs.read(String)} (#{rs.read(Int32)})"
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# => Sarah (33)
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# => John Doe (30)
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end
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end
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end
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```
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### DB::Any
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* `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).
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* `Bool` is implemented as `INT` column mapping `0`/`1` values.
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### Setting PRAGMAs
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You can adjust certain [SQLite3 PRAGMAs](https://www.sqlite.org/pragma.html)
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automatically when the connection is created by using the query parameters:
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```crystal
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require "sqlite3"
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DB.open "sqlite3://./data.db?journal_mode=wal&synchronous=normal" do |db|
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# this database now uses WAL journal and normal synchronous mode
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# (defaults were `delete` and `full`, respectively)
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end
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```
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The following is the list of supported options:
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| Name | Connection key |
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|---------------------------|-----------------|
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| [Busy Timeout][pragma-to] | `busy_timeout` |
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| [Cache Size][pragma-cs] | `cache_size` |
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| [Foreign Keys][pragma-fk] | `foreign_keys` |
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| [Journal Mode][pragma-jm] | `journal_mode` |
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| [Synchronous][pragma-sync] | `synchronous` |
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| [WAL autocheckoint][pragma-walck] | `wal_autocheckpoint` |
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Please note there values passed using these connection keys are passed
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directly to SQLite3 without check or evaluation. Using incorrect values result
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in no error by the library.
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[pragma-to]: https://www.sqlite.org/pragma.html#pragma_busy_timeout
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[pragma-cs]: https://www.sqlite.org/pragma.html#pragma_cache_size
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[pragma-fk]: https://www.sqlite.org/pragma.html#pragma_foreign_keys
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[pragma-jm]: https://www.sqlite.org/pragma.html#pragma_journal_mode
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[pragma-sync]: https://www.sqlite.org/pragma.html#pragma_synchronous
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[pragma-walck]: https://www.sqlite.org/pragma.html#pragma_wal_autocheckpoint
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