class CQL::Schema

• CQL::Schema
• Reference
• Object

Overview

The Schema class represents a database schema.

This class provides methods to build and manage a database schema, including creating tables, executing SQL statements, and generating queries.

Example Creating a new schema

schema = CQL::Schema.define(:northwind, "sqlite3://db.sqlite3") do
  table :users do
    primary :id, Int32, auto_increment: true
    column :name, String
    column :email, String
  end
end

Example Executing a SQL statement

schema.exec("CREATE TABLE products (id INTEGER PRIMARY KEY, name TEXT)")

Example Creating a new query

query = schema.query

The Schema class represents a database schema.

Defined in:

Constant Summary

Log = ::Log.for(self)

Constructors

• .new(name : Symbol, uri : String, adapter : Adapter, version : String = "1.0")

  Initializes a new schema.

Class Method Summary

• .define(name : Symbol, uri : String, adapter : Adapter, version : String = "1.0", &)

  Builds a new schema.

Macro Summary

• method_missing(call)

Instance Method Summary

• #adapter : Adapter
  • @return [Adapter] the database adapter (default: Adapter::SQLite)
• #alter(table_name : Symbol, &)

  Alter a table in the schema.

• #build

  Builds the schema.

• #delete

  Creates a new delete query for the schema.

• #dialect
• #dump_structure(file = "db/structure.sql")

  TODO For each adapter implement dumping the database structure tp a file called structure.sql.

• #exec(sql : String)

  Executes a SQL statement.

• #exec_query(&)
• #finalize

  Ensures the database connection is closed when the schema is garbage collected

• #gen : Expression::Generator
  • @return [Expression::Generator] the expression generator
• #insert

  Creates a new insert query for the schema.

• #migrator

  Creates a new migrator for the schema.

• #name : Symbol
  • @return [Symbol] the name of the schema
• #query

  Creates a new query for the schema.

• #table(name : Symbol, as as_name : Symbol | Nil = nil, &)

  Creates a new table in the schema.

• #table(name : Symbol, as as_name : String | Nil = nil, &)
• #tables : Hash(Symbol, Table)
  • @return [Hash(Symbol, Table)] the tables in the schema
• #update

  Creates a new update query for the schema.

• #uri : String
  • @return [String] the URI of the database
• #version : String
  • @return [String] the version of the schema

Constructor Detail

schema = CQL::Schema.new(:northwind, "sqlite3://db.sqlite3")

Class Method Detail

schema = CQL::Schema.define(:northwind, "sqlite3://db.sqlite3") do |s|
  s.create_table :users do
    primary :id, Int32, auto_increment: true
    column :name, String
    column :email, String
  end
end

Macro Detail

Instance Method Detail

schema.alter(:users) do |t|
  t.add_column :age, Int32
end

schema.alter(:users) do |t|
  t.drop_column :age
end

Schema.define

delete = schema.delete

schema.dump_structure

schema.dump_structure("db/structure.sql")

schema.exec("CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT)")

insert = schema.insert

migrator = schema.migrator

query = schema.query

schema.create_table :users do
  primary :id, Int32, auto_increment: true
  column :name, String
  column :email, String
end

update = schema.update