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sql.rb
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sql.rb
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module Sequel
class Dataset
AND_SEPARATOR = " AND ".freeze
BOOL_FALSE = "'f'".freeze
BOOL_TRUE = "'t'".freeze
COLUMN_REF_RE1 = /\A([\w ]+)__([\w ]+)___([\w ]+)\z/.freeze
COLUMN_REF_RE2 = /\A([\w ]+)___([\w ]+)\z/.freeze
COLUMN_REF_RE3 = /\A([\w ]+)__([\w ]+)\z/.freeze
COUNT_FROM_SELF_OPTS = [:distinct, :group, :sql, :limit]
DATE_FORMAT = "DATE '%Y-%m-%d'".freeze
N_ARITY_OPERATORS = ::Sequel::SQL::ComplexExpression::N_ARITY_OPERATORS
NULL = "NULL".freeze
QUESTION_MARK = '?'.freeze
STOCK_COUNT_OPTS = {:select => ["COUNT(*)".lit], :order => nil}.freeze
SELECT_CLAUSE_ORDER = %w'distinct columns from join where group having intersect union except order limit'.freeze
TIMESTAMP_FORMAT = "TIMESTAMP '%Y-%m-%d %H:%M:%S'".freeze
TWO_ARITY_OPERATORS = ::Sequel::SQL::ComplexExpression::TWO_ARITY_OPERATORS
WILDCARD = '*'.freeze
# Adds an further filter to an existing filter using AND. If no filter
# exists an error is raised. This method is identical to #filter except
# it expects an existing filter.
def and(*cond, &block)
raise(Error::NoExistingFilter, "No existing filter found.") unless @opts[:having] || @opts[:where]
filter(*cond, &block)
end
# SQL fragment for the aliased expression
def aliased_expression_sql(ae)
as_sql(literal(ae.expression), ae.aliaz)
end
# SQL fragment for the SQL array.
def array_sql(a)
a.empty? ? '(NULL)' : "(#{expression_list(a)})"
end
# SQL fragment for specifying given CaseExpression.
def case_expression_sql(ce)
sql = '(CASE '
sql << "#{literal(ce.expression)} " if ce.expression
ce.conditions.collect{ |c,r|
sql << "WHEN #{literal(c)} THEN #{literal(r)} "
}
sql << "ELSE #{literal(ce.default)} END)"
end
# SQL fragment for specifying all columns in a given table.
def column_all_sql(ca)
"#{quote_schema_table(ca.table)}.*"
end
# SQL fragment for complex expressions
def complex_expression_sql(op, args)
case op
when *TWO_ARITY_OPERATORS
"(#{literal(args.at(0))} #{op} #{literal(args.at(1))})"
when *N_ARITY_OPERATORS
"(#{args.collect{|a| literal(a)}.join(" #{op} ")})"
when :NOT
"NOT #{literal(args.at(0))}"
when :NOOP
literal(args.at(0))
when :'B~'
"~#{literal(args.at(0))}"
else
raise(Sequel::Error, "invalid operator #{op}")
end
end
# Returns the number of records in the dataset.
def count
options_overlap(COUNT_FROM_SELF_OPTS) ? from_self.count : single_value(STOCK_COUNT_OPTS).to_i
end
alias_method :size, :count
# Formats a DELETE statement using the given options and dataset options.
#
# dataset.filter(:price >= 100).delete_sql #=>
# "DELETE FROM items WHERE (price >= 100)"
def delete_sql(opts = nil)
opts = opts ? @opts.merge(opts) : @opts
return static_sql(opts[:sql]) if opts[:sql]
if opts[:group]
raise Error::InvalidOperation, "Grouped datasets cannot be deleted from"
elsif opts[:from].is_a?(Array) && opts[:from].size > 1
raise Error::InvalidOperation, "Joined datasets cannot be deleted from"
end
sql = "DELETE FROM #{source_list(opts[:from])}"
if where = opts[:where]
sql << " WHERE #{literal(where)}"
end
sql
end
# Adds an EXCEPT clause using a second dataset object. If all is true the
# clause used is EXCEPT ALL, which may return duplicate rows.
#
# DB[:items].except(DB[:other_items]).sql
# #=> "SELECT * FROM items EXCEPT SELECT * FROM other_items"
def except(dataset, all = false)
clone(:except => dataset, :except_all => all)
end
# Performs the inverse of Dataset#filter.
#
# dataset.exclude(:category => 'software').sql #=>
# "SELECT * FROM items WHERE (category != 'software')"
def exclude(*cond, &block)
clause = (@opts[:having] ? :having : :where)
cond = cond.first if cond.size == 1
cond = cond.sql_or if (Hash === cond) || ((Array === cond) && (cond.all_two_pairs?))
cond = filter_expr(cond, &block)
cond = SQL::BooleanExpression.invert(cond)
cond = SQL::BooleanExpression.new(:AND, @opts[clause], cond) if @opts[clause]
clone(clause => cond)
end
# Returns an EXISTS clause for the dataset as a LiteralString.
#
# DB.select(1).where(DB[:items].exists).sql
# #=> "SELECT 1 WHERE EXISTS (SELECT * FROM items)"
def exists(opts = nil)
"EXISTS (#{select_sql(opts)})".lit
end
# Returns a copy of the dataset with the given conditions imposed upon it.
# If the query has been grouped, then the conditions are imposed in the
# HAVING clause. If not, then they are imposed in the WHERE clause. Filter
#
# filter accepts the following argument types:
#
# * Hash - list of equality expressions
# * Array - depends:
# * If first member is a string, assumes the rest of the arguments
# are parameters and interpolates them into the string.
# * If all members are arrays of length two, treats the same way
# as a hash, except it allows for duplicate keys to be
# specified.
# * String - taken literally
# * Symbol - taken as a boolean column argument (e.g. WHERE active)
# * Sequel::SQL::BooleanExpression - an existing condition expression,
# probably created using the Sequel blockless filter DSL.
#
# filter also takes a block, which should return one of the above argument
# types, and is treated the same way. If both a block and regular argument
# are provided, they get ANDed together.
#
# Examples:
#
# dataset.filter(:id => 3).sql #=>
# "SELECT * FROM items WHERE (id = 3)"
# dataset.filter('price < ?', 100).sql #=>
# "SELECT * FROM items WHERE price < 100"
# dataset.filter([[:id, (1,2,3)], [:id, 0..10]]).sql #=>
# "SELECT * FROM items WHERE ((id IN (1, 2, 3)) AND ((id >= 0) AND (id <= 10)))"
# dataset.filter('price < 100').sql #=>
# "SELECT * FROM items WHERE price < 100"
# dataset.filter(:active).sql #=>
# "SELECT * FROM items WHERE :active
# dataset.filter(:price < 100).sql #=>
# "SELECT * FROM items WHERE (price < 100)"
#
# Multiple filter calls can be chained for scoping:
#
# software = dataset.filter(:category => 'software')
# software.filter(price < 100).sql #=>
# "SELECT * FROM items WHERE ((category = 'software') AND (price < 100))"
#
# See doc/dataset_filters.rdoc for more examples and details.
def filter(*cond, &block)
clause = (@opts[:having] ? :having : :where)
cond = cond.first if cond.size == 1
cond = transform_save(cond) if @transform if cond.is_a?(Hash)
cond = filter_expr(cond, &block)
cond = SQL::BooleanExpression.new(:AND, @opts[clause], cond) if @opts[clause] && !@opts[clause].blank?
clone(clause => cond)
end
alias_method :where, :filter
# The first source (primary table) for this dataset. If the dataset doesn't
# have a table, raises an error. If the table is aliased, returns the actual
# table name, not the alias.
def first_source
source = @opts[:from]
if source.nil? || source.empty?
raise Error, 'No source specified for query'
end
case s = source.first
when Hash
s.values.first
when Symbol
sch, table, aliaz = split_symbol(s)
aliaz ? aliaz.to_sym : s
else
s
end
end
# Returns a copy of the dataset with the source changed.
def from(*source)
clone(:from => source)
end
# Returns a dataset selecting from the current dataset.
#
# ds = DB[:items].order(:name)
# ds.sql #=> "SELECT * FROM items ORDER BY name"
# ds.from_self.sql #=> "SELECT * FROM (SELECT * FROM items ORDER BY name)"
def from_self
fs = {}
@opts.keys.each{|k| fs[k] = nil}
fs[:from] = [self]
clone(fs)
end
# SQL fragment specifying an SQL function call
def function_sql(f)
args = f.args
"#{f.f}#{args.empty? ? '()' : literal(args)}"
end
# Pattern match any of the columns to any of the terms. The terms can be
# strings (which use LIKE) or regular expressions (which are only supported
# in some databases). See Sequel::SQL::StringExpression.like. Note that the
# total number of pattern matches will be cols.length * terms.length,
# which could cause performance issues.
def grep(cols, terms)
filter(SQL::BooleanExpression.new(:OR, *Array(cols).collect{|c| SQL::StringExpression.like(c, *terms)}))
end
# Returns a copy of the dataset with the results grouped by the value of
# the given columns
def group(*columns)
clone(:group => columns)
end
alias_method :group_by, :group
# Returns a copy of the dataset with the having conditions changed. Raises
# an error if the dataset has not been grouped. See also #filter.
def having(*cond, &block)
raise(Error::InvalidOperation, "Can only specify a HAVING clause on a grouped dataset") unless @opts[:group]
clone(:having=>{}).filter(*cond, &block)
end
# Inserts multiple values. If a block is given it is invoked for each
# item in the given array before inserting it. See #multi_insert as
# a possible faster version that inserts multiple records in one
# SQL statement.
def insert_multiple(array, &block)
if block
array.each {|i| insert(block[i])}
else
array.each {|i| insert(i)}
end
end
# Formats an INSERT statement using the given values. If a hash is given,
# the resulting statement includes column names. If no values are given,
# the resulting statement includes a DEFAULT VALUES clause.
#
# dataset.insert_sql() #=> 'INSERT INTO items DEFAULT VALUES'
# dataset.insert_sql(1,2,3) #=> 'INSERT INTO items VALUES (1, 2, 3)'
# dataset.insert_sql(:a => 1, :b => 2) #=>
# 'INSERT INTO items (a, b) VALUES (1, 2)'
def insert_sql(*values)
return static_sql(@opts[:sql]) if @opts[:sql]
from = source_list(@opts[:from])
case values.size
when 0
values = {}
when 1
vals = values.at(0)
if vals.is_one_of?(Hash, Dataset, Array)
values = vals
elsif vals.respond_to?(:values)
values = vals.values
end
end
case values
when Array
if values.empty?
insert_default_values_sql
else
"INSERT INTO #{from} VALUES #{literal(values)}"
end
when Hash
values = @opts[:defaults].merge(values) if @opts[:defaults]
values = values.merge(@opts[:overrides]) if @opts[:overrides]
values = transform_save(values) if @transform
if values.empty?
insert_default_values_sql
else
fl, vl = [], []
values.each do |k, v|
fl << literal(String === k ? k.to_sym : k)
vl << literal(v)
end
"INSERT INTO #{from} (#{fl.join(COMMA_SEPARATOR)}) VALUES (#{vl.join(COMMA_SEPARATOR)})"
end
when Dataset
"INSERT INTO #{from} #{literal(values)}"
end
end
# Adds an INTERSECT clause using a second dataset object. If all is true
# the clause used is INTERSECT ALL, which may return duplicate rows.
#
# DB[:items].intersect(DB[:other_items]).sql
# #=> "SELECT * FROM items INTERSECT SELECT * FROM other_items"
def intersect(dataset, all = false)
clone(:intersect => dataset, :intersect_all => all)
end
# Inverts the current filter
#
# dataset.filter(:category => 'software').invert.sql #=>
# "SELECT * FROM items WHERE (category != 'software')"
def invert
having, where = @opts[:having], @opts[:where]
raise(Error, "No current filter") unless having || where
o = {}
o[:having] = SQL::BooleanExpression.invert(having) if having
o[:where] = SQL::BooleanExpression.invert(where) if where
clone(o)
end
# SQL fragment specifying an Irregular (cast/extract) SQL function call
def irregular_function_sql(f)
"#{f.f}(#{literal(f.arg1)} #{f.joiner} #{literal(f.arg2)})"
end
# SQL fragment specifying a JOIN clause without ON or USING.
def join_clause_sql(jc)
table = jc.table
table_alias = jc.table_alias
table_alias = nil if table == table_alias
tref = table_ref(table)
" #{join_type_sql(jc.join_type)} #{table_alias ? as_sql(tref, table_alias) : tref}"
end
# SQL fragment specifying a JOIN clause with ON.
def join_on_clause_sql(jc)
"#{join_clause_sql(jc)} ON #{literal(filter_expr(jc.on))}"
end
# SQL fragment specifying a JOIN clause with USING.
def join_using_clause_sql(jc)
"#{join_clause_sql(jc)} USING (#{column_list(jc.using)})"
end
# Returns a joined dataset. Uses the following arguments:
#
# * type - The type of join to do (:inner, :left_outer, :right_outer, :full)
# * table - Depends on type:
# * Dataset - a subselect is performed with an alias of tN for some value of N
# * Model (or anything responding to :table_name) - table.table_name
# * String, Symbol: table
# * expr - specifies conditions, depends on type:
# * Hash, Array with all two pairs - Assumes key (1st arg) is column of joined table (unless already
# qualified), and value (2nd arg) is column of the last joined or primary table (or the
# :implicit_qualifier option).
# To specify multiple conditions on a single joined table column, you must use an array.
# Uses a JOIN with an ON clause.
# * Array - If all members of the array are symbols, considers them as columns and
# uses a JOIN with a USING clause. Most databases will remove duplicate columns from
# the result set if this is used.
# * nil - If a block is not given, doesn't use ON or USING, so the JOIN should be a NATURAL
# or CROSS join. If a block is given, uses a ON clause based on the block, see below.
# * Everything else - pretty much the same as a using the argument in a call to filter,
# so strings are considered literal, symbols specify boolean columns, and blockless
# filter expressions can be used. Uses a JOIN with an ON clause.
# * options - a hash of options, with any of the following keys:
# * :table_alias - the name of the table's alias when joining, necessary for joining
# to the same table more than once. No alias is used by default.
# * :implicit_qualifer - The name to use for qualifying implicit conditions. By default,
# the last joined or primary table is used.
# * block - The block argument should only be given if a JOIN with an ON clause is used,
# in which case it yields the table alias/name for the table currently being joined,
# the table alias/name for the last joined (or first table), and an array of previous
# SQL::JoinClause.
def join_table(type, table, expr=nil, options={}, &block)
if options.is_one_of?(Symbol, String)
table_alias = options
last_alias = nil
else
table_alias = options[:table_alias]
last_alias = options[:implicit_qualifier]
end
if Dataset === table
if table_alias.nil?
table_alias_num = (@opts[:num_dataset_sources] || 0) + 1
table_alias = "t#{table_alias_num}"
end
table_name = table_alias
else
table = table.table_name if table.respond_to?(:table_name)
table_name = table_alias || table
end
join = if expr.nil? and !block_given?
SQL::JoinClause.new(type, table, table_alias)
elsif Array === expr and !expr.empty? and expr.all?{|x| Symbol === x}
raise(Sequel::Error, "can't use a block if providing an array of symbols as expr") if block_given?
SQL::JoinUsingClause.new(expr, type, table, table_alias)
else
last_alias ||= @opts[:last_joined_table] || (first_source.is_a?(Dataset) ? 't1' : first_source)
if Hash === expr or (Array === expr and expr.all_two_pairs?)
expr = expr.collect do |k, v|
k = qualified_column_name(k, table_name) if k.is_a?(Symbol)
v = qualified_column_name(v, last_alias) if v.is_a?(Symbol)
[k,v]
end
end
if block_given?
expr2 = yield(table_name, last_alias, @opts[:join] || [])
expr = expr ? SQL::BooleanExpression.new(:AND, expr, expr2) : expr2
end
SQL::JoinOnClause.new(expr, type, table, table_alias)
end
opts = {:join => (@opts[:join] || []) + [join], :last_joined_table => table_name}
opts[:num_dataset_sources] = table_alias_num if table_alias_num
clone(opts)
end
# If given an integer, the dataset will contain only the first l results.
# If given a range, it will contain only those at offsets within that
# range. If a second argument is given, it is used as an offset.
def limit(l, o = nil)
return from_self.limit(l, o) if @opts[:sql]
if Range === l
o = l.first
l = l.interval + 1
end
l = l.to_i
raise(Error, 'Limits must be greater than or equal to 1') unless l >= 1
opts = {:limit => l}
if o
o = o.to_i
raise(Error, 'Offsets must be greater than or equal to 0') unless o >= 0
opts[:offset] = o
end
clone(opts)
end
# Returns a literal representation of a value to be used as part
# of an SQL expression.
#
# dataset.literal("abc'def\\") #=> "'abc''def\\\\'"
# dataset.literal(:items__id) #=> "items.id"
# dataset.literal([1, 2, 3]) => "(1, 2, 3)"
# dataset.literal(DB[:items]) => "(SELECT * FROM items)"
# dataset.literal(:x + 1 > :y) => "((x + 1) > y)"
#
# If an unsupported object is given, an exception is raised.
def literal(v)
case v
when LiteralString
v
when String
"'#{v.gsub(/\\/, "\\\\\\\\").gsub(/'/, "''")}'"
when Integer, Float
v.to_s
when BigDecimal
v.to_s("F")
when NilClass
NULL
when TrueClass
BOOL_TRUE
when FalseClass
BOOL_FALSE
when Symbol
symbol_to_column_ref(v)
when ::Sequel::SQL::Expression
v.to_s(self)
when Array
v.all_two_pairs? ? literal(v.sql_expr) : array_sql(v)
when Hash
literal(v.sql_expr)
when Time, DateTime
v.strftime(TIMESTAMP_FORMAT)
when Date
v.strftime(DATE_FORMAT)
when Dataset
"(#{subselect_sql(v)})"
else
raise Error, "can't express #{v.inspect} as a SQL literal"
end
end
# Returns an array of insert statements for inserting multiple records.
# This method is used by #multi_insert to format insert statements and
# expects a keys array and and an array of value arrays.
#
# This method should be overridden by descendants if the support
# inserting multiple records in a single SQL statement.
def multi_insert_sql(columns, values)
table = quote_identifier(@opts[:from].first)
columns = identifier_list(columns)
values.map do |r|
"INSERT INTO #{table} (#{columns}) VALUES #{literal(r)}"
end
end
# Adds an alternate filter to an existing filter using OR. If no filter
# exists an error is raised.
def or(*cond, &block)
clause = (@opts[:having] ? :having : :where)
cond = cond.first if cond.size == 1
if @opts[clause]
clone(clause => SQL::BooleanExpression.new(:OR, @opts[clause], filter_expr(cond, &block)))
else
raise Error::NoExistingFilter, "No existing filter found."
end
end
# Returns a copy of the dataset with the order changed. If a nil is given
# the returned dataset has no order. This can accept multiple arguments
# of varying kinds, and even SQL functions.
#
# ds.order(:name).sql #=> 'SELECT * FROM items ORDER BY name'
# ds.order(:a, :b).sql #=> 'SELECT * FROM items ORDER BY a, b'
# ds.order('a + b'.lit).sql #=> 'SELECT * FROM items ORDER BY a + b'
# ds.order(:a + :b).sql #=> 'SELECT * FROM items ORDER BY (a + b)'
# ds.order(:name.desc).sql #=> 'SELECT * FROM items ORDER BY name DESC'
# ds.order(:name.asc).sql #=> 'SELECT * FROM items ORDER BY name ASC'
# ds.order(:arr|1).sql #=> 'SELECT * FROM items ORDER BY arr[1]'
# ds.order(nil).sql #=> 'SELECT * FROM items'
def order(*order)
clone(:order => (order.compact.empty?) ? nil : order)
end
alias_method :order_by, :order
# Returns a copy of the dataset with the order columns added
# to the existing order.
def order_more(*order)
order(*((@opts[:order] || []) + order))
end
# SQL fragment for the ordered expression, used in the ORDER BY
# clause.
def ordered_expression_sql(oe)
"#{literal(oe.expression)} #{oe.descending ? 'DESC' : 'ASC'}"
end
# SQL fragment for a literal string with placeholders
def placeholder_literal_string_sql(pls)
args = pls.args.dup
s = pls.str.gsub(QUESTION_MARK){literal(args.shift)}
s = "(#{s})" if pls.parens
s
end
# SQL fragment for the qualifed identifier, specifying
# a table and a column (or schema and table).
def qualified_identifier_sql(qcr)
[qcr.table, qcr.column].map{|x| x.is_one_of?(SQL::QualifiedIdentifier, SQL::Identifier, Symbol) ? literal(x) : quote_identifier(x)}.join('.')
end
# Adds quoting to identifiers (columns and tables). If identifiers are not
# being quoted, returns name as a string. If identifiers are being quoted
# quote the name with quoted_identifier.
def quote_identifier(name)
name = name.to_s
name = name.upcase if upcase_identifiers?
name = quoted_identifier(name) if quote_identifiers?
name
end
alias_method :quote_column_ref, :quote_identifier
# Separates the schema from the table and returns a string with them
# quoted (if quoting identifiers)
def quote_schema_table(table)
schema, table = schema_and_table(table)
"#{"#{quote_identifier(schema)}." if schema}#{quote_identifier(table)}"
end
# This method quotes the given name with the SQL standard double quote.
# should be overridden by subclasses to provide quoting not matching the
# SQL standard, such as backtick (used by MySQL and SQLite).
def quoted_identifier(name)
"\"#{name}\""
end
# Returns a copy of the dataset with the order reversed. If no order is
# given, the existing order is inverted.
def reverse_order(*order)
order(*invert_order(order.empty? ? @opts[:order] : order))
end
alias_method :reverse, :reverse_order
# Split the schema information from the table
def schema_and_table(table_name)
sch = db.default_schema if db
case table_name
when Symbol
s, t, a = split_symbol(table_name)
[s||sch, t]
when SQL::QualifiedIdentifier
[table_name.table, table_name.column]
when SQL::Identifier
[sch, table_name.value]
when String
[sch, table_name]
else
raise Error, 'table_name should be a Symbol, SQL::QualifiedIdentifier, SQL::Identifier, or String'
end
end
# Returns a copy of the dataset with the columns selected changed
# to the given columns.
def select(*columns)
clone(:select => columns)
end
# Returns a copy of the dataset selecting the wildcard.
def select_all
clone(:select => nil)
end
# Returns a copy of the dataset with the given columns added
# to the existing selected columns.
def select_more(*columns)
select(*((@opts[:select] || []) + columns))
end
# Formats a SELECT statement using the given options and the dataset
# options.
def select_sql(opts = nil)
opts = opts ? @opts.merge(opts) : @opts
return static_sql(opts[:sql]) if opts[:sql]
sql = 'SELECT'
select_clause_order.each{|x| send("select_#{x}_sql", sql, opts)}
sql
end
# Same as select_sql, not aliased directly to make subclassing simpler.
def sql(*args)
select_sql(*args)
end
# SQL fragment for specifying subscripts (SQL arrays)
def subscript_sql(s)
"#{s.f}[#{s.sub.join(COMMA_SEPARATOR)}]"
end
# Converts a symbol into a column name. This method supports underscore
# notation in order to express qualified (two underscores) and aliased
# (three underscores) columns:
#
# ds = DB[:items]
# :abc.to_column_ref(ds) #=> "abc"
# :abc___a.to_column_ref(ds) #=> "abc AS a"
# :items__abc.to_column_ref(ds) #=> "items.abc"
# :items__abc___a.to_column_ref(ds) #=> "items.abc AS a"
#
def symbol_to_column_ref(sym)
c_table, column, c_alias = split_symbol(sym)
qc = "#{"#{quote_identifier(c_table)}." if c_table}#{quote_identifier(column)}"
c_alias ? as_sql(qc, c_alias) : qc
end
# Returns a copy of the dataset with no filters (HAVING or WHERE clause) applied.
def unfiltered
clone(:where => nil, :having => nil)
end
# Adds a UNION clause using a second dataset object. If all is true the
# clause used is UNION ALL, which may return duplicate rows.
#
# DB[:items].union(DB[:other_items]).sql
# #=> "SELECT * FROM items UNION SELECT * FROM other_items"
def union(dataset, all = false)
clone(:union => dataset, :union_all => all)
end
# Returns a copy of the dataset with the distinct option.
def uniq(*args)
clone(:distinct => args)
end
alias_method :distinct, :uniq
# Returns a copy of the dataset with no order.
def unordered
order(nil)
end
# Formats an UPDATE statement using the given values.
#
# dataset.update_sql(:price => 100, :category => 'software') #=>
# "UPDATE items SET price = 100, category = 'software'"
#
# Accepts a block, but such usage is discouraged.
#
# Raises an error if the dataset is grouped or includes more
# than one table.
def update_sql(values = {}, opts = nil)
opts = opts ? @opts.merge(opts) : @opts
return static_sql(opts[:sql]) if opts[:sql]
if opts[:group]
raise Error::InvalidOperation, "A grouped dataset cannot be updated"
elsif (opts[:from].size > 1) or opts[:join]
raise Error::InvalidOperation, "A joined dataset cannot be updated"
end
sql = "UPDATE #{source_list(@opts[:from])} SET "
set = if values.is_a?(Hash)
values = opts[:defaults].merge(values) if opts[:defaults]
values = values.merge(opts[:overrides]) if opts[:overrides]
# get values from hash
values = transform_save(values) if @transform
values.map do |k, v|
"#{k.is_one_of?(String, Symbol) ? quote_identifier(k) : literal(k)} = #{literal(v)}"
end.join(COMMA_SEPARATOR)
else
# copy values verbatim
values
end
sql << set
if where = opts[:where]
sql << " WHERE #{literal(where)}"
end
sql
end
[:inner, :full_outer, :right_outer, :left_outer].each do |jtype|
class_eval("def #{jtype}_join(*args, &block); join_table(:#{jtype}, *args, &block) end")
end
alias_method :join, :inner_join
protected
# Returns a table reference for use in the FROM clause. Returns an SQL subquery
# frgament with an optional table alias.
def to_table_reference(table_alias=nil)
s = "(#{sql})"
table_alias ? as_sql(s, table_alias) : s
end
private
# SQL fragment for specifying an alias. expression should already be literalized.
def as_sql(expression, aliaz)
"#{expression} AS #{quote_identifier(aliaz)}"
end
# Converts an array of column names into a comma seperated string of
# column names. If the array is empty, a wildcard (*) is returned.
def column_list(columns)
if columns.blank?
WILDCARD
else
m = columns.map do |i|
i.is_a?(Hash) ? i.map{|k, v| as_sql(literal(k), v)} : literal(i)
end
m.join(COMMA_SEPARATOR)
end
end
# Converts an array of expressions into a comma separated string of
# expressions.
def expression_list(columns)
columns.map{|i| literal(i)}.join(COMMA_SEPARATOR)
end
# SQL fragment based on the expr type. See #filter.
def filter_expr(expr = nil, &block)
expr = nil if expr == []
if expr && block
return SQL::BooleanExpression.new(:AND, filter_expr(expr), filter_expr(block))
elsif block
expr = block
end
case expr
when Hash
SQL::BooleanExpression.from_value_pairs(expr)
when Array
if String === expr[0]
SQL::PlaceholderLiteralString.new(expr.shift, expr, true)
else
SQL::BooleanExpression.from_value_pairs(expr)
end
when Proc
filter_expr(expr.call(SQL::VirtualRow.new))
when SQL::NumericExpression, SQL::StringExpression
raise(Error, "Invalid SQL Expression type: #{expr.inspect}")
when Symbol, SQL::Expression
expr
when TrueClass, FalseClass
SQL::BooleanExpression.new(:NOOP, expr)
when String
"(#{expr})".lit
else
raise(Error, 'Invalid filter argument')
end
end
# SQL fragment specifying a list of identifiers
def identifier_list(columns)
columns.map{|i| quote_identifier(i)}.join(COMMA_SEPARATOR)
end
# SQL statement for formatting an insert statement with default values
def insert_default_values_sql
"INSERT INTO #{source_list(@opts[:from])} DEFAULT VALUES"
end
# Inverts the given order by breaking it into a list of column references
# and inverting them.
#
# dataset.invert_order([:id.desc]]) #=> [:id]
# dataset.invert_order(:category, :price.desc]) #=>
# [:category.desc, :price]
def invert_order(order)
return nil unless order
new_order = []
order.map do |f|
case f
when SQL::OrderedExpression
SQL::OrderedExpression.new(f.expression, !f.descending)
else
SQL::OrderedExpression.new(f)
end
end
end
# SQL fragment specifying a JOIN type, converts underscores to
# spaces and upcases.
def join_type_sql(join_type)
"#{join_type.to_s.gsub('_', ' ').upcase} JOIN"
end
# Returns a qualified column name (including a table name) if the column
# name isn't already qualified.
def qualified_column_name(column, table)
if Symbol === column
c_table, column, c_alias = split_symbol(column)
unless c_table
case table
when Symbol
schema, table, t_alias = split_symbol(table)
t_alias ||= Sequel::SQL::QualifiedIdentifier.new(schema, table) if schema
when Sequel::SQL::AliasedExpression
t_alias = table.aliaz
end
c_table = t_alias || table
end
::Sequel::SQL::QualifiedIdentifier.new(c_table, column)
else
column
end
end
# The order of methods to call to build the SELECT SQL statement
def select_clause_order
SELECT_CLAUSE_ORDER
end
# Modify the sql to add the columns selected
def select_columns_sql(sql, opts)
sql << " #{column_list(opts[:select])}"
end
# Modify the sql to add the DISTINCT modifier
def select_distinct_sql(sql, opts)
if distinct = opts[:distinct]
sql << " DISTINCT#{" ON (#{expression_list(distinct)})" unless distinct.empty?}"
end
end
# Modify the sql to add a dataset to the EXCEPT clause
def select_except_sql(sql, opts)
sql << " EXCEPT#{' ALL' if opts[:except_all]} #{opts[:except].sql}" if opts[:except]
end
# Modify the sql to add the list of tables to select FROM
def select_from_sql(sql, opts)
sql << " FROM #{source_list(opts[:from])}" if opts[:from]
end
# Modify the sql to add the expressions to GROUP BY
def select_group_sql(sql, opts)
sql << " GROUP BY #{expression_list(opts[:group])}" if opts[:group]
end
# Modify the sql to add the filter criteria in the HAVING clause
def select_having_sql(sql, opts)
sql << " HAVING #{literal(opts[:having])}" if opts[:having]
end
# Modify the sql to add a dataset to the INTERSECT clause
def select_intersect_sql(sql, opts)
sql << " INTERSECT#{' ALL' if opts[:intersect_all]} #{opts[:intersect].sql}" if opts[:intersect]
end
# Modify the sql to add the list of tables to JOIN to
def select_join_sql(sql, opts)
opts[:join].each{|j| sql << literal(j)} if opts[:join]
end
# Modify the sql to limit the number of rows returned and offset
def select_limit_sql(sql, opts)
sql << " LIMIT #{opts[:limit]}" if opts[:limit]
sql << " OFFSET #{opts[:offset]}" if opts[:offset]
end
# Modify the sql to add the expressions to ORDER BY
def select_order_sql(sql, opts)
sql << " ORDER BY #{expression_list(opts[:order])}" if opts[:order]
end
# Modify the sql to add a dataset to the UNION clause
def select_union_sql(sql, opts)
sql << " UNION#{' ALL' if opts[:union_all]} #{opts[:union].sql}" if opts[:union]
end
# Modify the sql to add the filter criteria in the WHERE clause
def select_where_sql(sql, opts)
sql << " WHERE #{literal(opts[:where])}" if opts[:where]
end
# Converts an array of source names into into a comma separated list.
def source_list(source)
if source.nil? || source.empty?
raise Error, 'No source specified for query'
end
auto_alias_count = @opts[:num_dataset_sources] || 0
m = source.map do |s|
case s
when Dataset
auto_alias_count += 1
s.to_table_reference("t#{auto_alias_count}")
else
table_ref(s)
end
end
m.join(COMMA_SEPARATOR)
end
# Splits the symbol into three parts. Each part will
# either be a string or nil.
#
# For columns, these parts are the table, column, and alias.
# For tables, these parts are the schema, table, and alias.
def split_symbol(sym)
s = sym.to_s
if m = COLUMN_REF_RE1.match(s)
m[1..3]
elsif m = COLUMN_REF_RE2.match(s)
[nil, m[1], m[2]]
elsif m = COLUMN_REF_RE3.match(s)
[m[1], m[2], nil]
else
[nil, s, nil]
end
end
# SQL to use if this dataset uses static SQL. Since static SQL
# can be a PlaceholderLiteralString in addition to a String,
# we literalize nonstrings.
def static_sql(sql)
sql.is_a?(String) ? sql : literal(sql)
end
# SQL fragment for a subselect using the given database's SQL.
def subselect_sql(ds)
ds.sql
end
# SQL fragment specifying a table name.
def table_ref(t)
case t
when Dataset
t.to_table_reference
when Hash
t.map{|k, v| as_sql(table_ref(k), v)}.join(COMMA_SEPARATOR)
when Symbol
symbol_to_column_ref(t)
when String
quote_identifier(t)
else
literal(t)
end
end
end
end