272 lines
10 KiB
Ruby
272 lines
10 KiB
Ruby
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module ActiveRecord
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module ConnectionAdapters # :nodoc:
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module SchemaStatements
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# Returns a Hash of mappings from the abstract data types to the native
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# database types. See TableDefinition#column for details on the recognized
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# abstract data types.
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def native_database_types
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{}
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end
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# This is the maximum length a table alias can be
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def table_alias_length
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255
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end
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# Truncates a table alias according to the limits of the current adapter.
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def table_alias_for(table_name)
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table_name[0..table_alias_length-1].gsub(/\./, '_')
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end
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# def tables(name = nil) end
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# Returns an array of indexes for the given table.
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# def indexes(table_name, name = nil) end
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# Returns an array of Column objects for the table specified by +table_name+.
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# See the concrete implementation for details on the expected parameter values.
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def columns(table_name, name = nil) end
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# Creates a new table
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# There are two ways to work with #create_table. You can use the block
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# form or the regular form, like this:
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#
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# === Block form
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# # create_table() yields a TableDefinition instance
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# create_table(:suppliers) do |t|
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# t.column :name, :string, :limit => 60
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# # Other fields here
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# end
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#
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# === Regular form
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# create_table(:suppliers)
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# add_column(:suppliers, :name, :string, {:limit => 60})
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#
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# The +options+ hash can include the following keys:
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# [<tt>:id</tt>]
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# Set to true or false to add/not add a primary key column
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# automatically. Defaults to true.
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# [<tt>:primary_key</tt>]
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# The name of the primary key, if one is to be added automatically.
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# Defaults to +id+.
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# [<tt>:options</tt>]
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# Any extra options you want appended to the table definition.
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# [<tt>:temporary</tt>]
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# Make a temporary table.
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# [<tt>:force</tt>]
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# Set to true or false to drop the table before creating it.
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# Defaults to false.
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#
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# ===== Examples
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# ====== Add a backend specific option to the generated SQL (MySQL)
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# create_table(:suppliers, :options => 'ENGINE=InnoDB DEFAULT CHARSET=utf8')
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# generates:
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# CREATE TABLE suppliers (
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# id int(11) DEFAULT NULL auto_increment PRIMARY KEY
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# ) ENGINE=InnoDB DEFAULT CHARSET=utf8
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#
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# ====== Rename the primary key column
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# create_table(:objects, :primary_key => 'guid') do |t|
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# t.column :name, :string, :limit => 80
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# end
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# generates:
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# CREATE TABLE objects (
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# guid int(11) DEFAULT NULL auto_increment PRIMARY KEY,
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# name varchar(80)
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# )
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#
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# ====== Do not add a primary key column
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# create_table(:categories_suppliers, :id => false) do |t|
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# t.column :category_id, :integer
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# t.column :supplier_id, :integer
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# end
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# generates:
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# CREATE TABLE categories_suppliers_join (
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# category_id int,
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# supplier_id int
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# )
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#
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# See also TableDefinition#column for details on how to create columns.
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def create_table(name, options = {})
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table_definition = TableDefinition.new(self)
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table_definition.primary_key(options[:primary_key] || "id") unless options[:id] == false
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yield table_definition
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if options[:force]
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drop_table(name) rescue nil
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end
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create_sql = "CREATE#{' TEMPORARY' if options[:temporary]} TABLE "
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create_sql << "#{name} ("
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create_sql << table_definition.to_sql
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create_sql << ") #{options[:options]}"
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execute create_sql
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end
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# Renames a table.
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# ===== Example
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# rename_table('octopuses', 'octopi')
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def rename_table(name, new_name)
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raise NotImplementedError, "rename_table is not implemented"
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end
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# Drops a table from the database.
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def drop_table(name)
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execute "DROP TABLE #{name}"
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end
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# Adds a new column to the named table.
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# See TableDefinition#column for details of the options you can use.
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def add_column(table_name, column_name, type, options = {})
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add_column_sql = "ALTER TABLE #{table_name} ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit])}"
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add_column_options!(add_column_sql, options)
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execute(add_column_sql)
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end
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# Removes the column from the table definition.
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# ===== Examples
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# remove_column(:suppliers, :qualification)
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def remove_column(table_name, column_name)
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execute "ALTER TABLE #{table_name} DROP #{quote_column_name(column_name)}"
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end
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# Changes the column's definition according to the new options.
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# See TableDefinition#column for details of the options you can use.
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# ===== Examples
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# change_column(:suppliers, :name, :string, :limit => 80)
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# change_column(:accounts, :description, :text)
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def change_column(table_name, column_name, type, options = {})
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raise NotImplementedError, "change_column is not implemented"
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end
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# Sets a new default value for a column. If you want to set the default
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# value to +NULL+, you are out of luck. You need to
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# DatabaseStatements#execute the apppropriate SQL statement yourself.
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# ===== Examples
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# change_column_default(:suppliers, :qualification, 'new')
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# change_column_default(:accounts, :authorized, 1)
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def change_column_default(table_name, column_name, default)
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raise NotImplementedError, "change_column_default is not implemented"
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end
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# Renames a column.
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# ===== Example
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# rename_column(:suppliers, :description, :name)
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def rename_column(table_name, column_name, new_column_name)
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raise NotImplementedError, "rename_column is not implemented"
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end
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# Adds a new index to the table. +column_name+ can be a single Symbol, or
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# an Array of Symbols.
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#
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# The index will be named after the table and the first column names,
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# unless you pass +:name+ as an option.
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#
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# When creating an index on multiple columns, the first column is used as a name
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# for the index. For example, when you specify an index on two columns
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# [+:first+, +:last+], the DBMS creates an index for both columns as well as an
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# index for the first colum +:first+. Using just the first name for this index
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# makes sense, because you will never have to create a singular index with this
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# name.
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#
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# ===== Examples
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# ====== Creating a simple index
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# add_index(:suppliers, :name)
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# generates
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# CREATE INDEX suppliers_name_index ON suppliers(name)
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# ====== Creating a unique index
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# add_index(:accounts, [:branch_id, :party_id], :unique => true)
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# generates
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# CREATE UNIQUE INDEX accounts_branch_id_index ON accounts(branch_id, party_id)
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# ====== Creating a named index
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# add_index(:accounts, [:branch_id, :party_id], :unique => true, :name => 'by_branch_party')
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# generates
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# CREATE UNIQUE INDEX by_branch_party ON accounts(branch_id, party_id)
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def add_index(table_name, column_name, options = {})
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column_names = Array(column_name)
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index_name = index_name(table_name, :column => column_names.first)
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if Hash === options # legacy support, since this param was a string
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index_type = options[:unique] ? "UNIQUE" : ""
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index_name = options[:name] || index_name
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else
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index_type = options
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end
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quoted_column_names = column_names.map { |e| quote_column_name(e) }.join(", ")
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execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{table_name} (#{quoted_column_names})"
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end
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# Remove the given index from the table.
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#
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# Remove the suppliers_name_index in the suppliers table (legacy support, use the second or third forms).
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# remove_index :suppliers, :name
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# Remove the index named accounts_branch_id in the accounts table.
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# remove_index :accounts, :column => :branch_id
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# Remove the index named by_branch_party in the accounts table.
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# remove_index :accounts, :name => :by_branch_party
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#
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# You can remove an index on multiple columns by specifying the first column.
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# add_index :accounts, [:username, :password]
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# remove_index :accounts, :username
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def remove_index(table_name, options = {})
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execute "DROP INDEX #{quote_column_name(index_name(table_name, options))} ON #{table_name}"
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end
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def index_name(table_name, options) #:nodoc:
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if Hash === options # legacy support
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if options[:column]
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"#{table_name}_#{options[:column]}_index"
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elsif options[:name]
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options[:name]
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else
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raise ArgumentError, "You must specify the index name"
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end
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else
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"#{table_name}_#{options}_index"
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end
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end
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# Returns a string of <tt>CREATE TABLE</tt> SQL statement(s) for recreating the
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# entire structure of the database.
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def structure_dump
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end
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# Should not be called normally, but this operation is non-destructive.
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# The migrations module handles this automatically.
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def initialize_schema_information
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begin
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execute "CREATE TABLE #{ActiveRecord::Migrator.schema_info_table_name} (version #{type_to_sql(:integer)})"
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execute "INSERT INTO #{ActiveRecord::Migrator.schema_info_table_name} (version) VALUES(0)"
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rescue ActiveRecord::StatementInvalid
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# Schema has been intialized
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end
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end
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def dump_schema_information #:nodoc:
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begin
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if (current_schema = ActiveRecord::Migrator.current_version) > 0
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return "INSERT INTO #{ActiveRecord::Migrator.schema_info_table_name} (version) VALUES (#{current_schema})"
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end
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rescue ActiveRecord::StatementInvalid
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# No Schema Info
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end
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end
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def type_to_sql(type, limit = nil) #:nodoc:
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native = native_database_types[type]
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limit ||= native[:limit]
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column_type_sql = native[:name]
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column_type_sql << "(#{limit})" if limit
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column_type_sql
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end
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def add_column_options!(sql, options) #:nodoc:
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sql << " DEFAULT #{quote(options[:default], options[:column])}" unless options[:default].nil?
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sql << " NOT NULL" if options[:null] == false
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end
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end
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end
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end
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