The allowed values for #insert_conflict
# File lib/sequel/adapters/shared/sqlite.rb, line 502 def cast_sql_append(sql, expr, type) if type == Time or type == DateTime sql << "datetime(" literal_append(sql, expr) sql << ')' elsif type == Date sql << "date(" literal_append(sql, expr) sql << ')' else super end end
SQLite doesn't support a NOT LIKE b, you need to use NOT (a LIKE b). It doesn't support xor, power, or the extract function natively, so those have to be emulated.
# File lib/sequel/adapters/shared/sqlite.rb, line 518 def complex_expression_sql_append(sql, op, args) case op when :"NOT LIKE", :"NOT ILIKE" sql << 'NOT ' complex_expression_sql_append(sql, (op == :"NOT ILIKE" ? :ILIKE : :LIKE), args) when :^ complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.lit(["((~(", " & ", ")) & (", " | ", "))"], a, b, a, b)} when :** unless (exp = args[1]).is_a?(Integer) raise(Sequel::Error, "can only emulate exponentiation on SQLite if exponent is an integer, given #{exp.inspect}") end case exp when 0 sql << '1' else sql << '(' arg = args[0] if exp < 0 invert = true exp = exp.abs sql << '(1.0 / (' end (exp - 1).times do literal_append(sql, arg) sql << " * " end literal_append(sql, arg) sql << ')' if invert sql << "))" end end when :extract part = args[0] raise(Sequel::Error, "unsupported extract argument: #{part.inspect}") unless format = EXTRACT_MAP[part] sql << "CAST(strftime(" << format << ', ' literal_append(sql, args[1]) sql << ') AS ' << (part == :second ? 'NUMERIC' : 'INTEGER') << ')' else super end end
SQLite has CURRENT_TIMESTAMP and related constants in UTC instead of in localtime, so convert those constants to local time.
# File lib/sequel/adapters/shared/sqlite.rb, line 563 def constant_sql_append(sql, constant) if c = CONSTANT_MAP[constant] sql << c else super end end
SQLite performs a TRUNCATE style DELETE if no filter is specified. Since we want to always return the count of records, add a condition that is always true and then delete.
# File lib/sequel/adapters/shared/sqlite.rb, line 574 def delete @opts[:where] ? super : where(1=>1).delete end
Return an array of strings specifying a query explanation for a SELECT of the current dataset. Currently, the options are ignored, but it accepts options to be compatible with other adapters.
# File lib/sequel/adapters/shared/sqlite.rb, line 581 def explain(opts=nil) # Load the PrettyTable class, needed for explain output Sequel.extension(:_pretty_table) unless defined?(Sequel::PrettyTable) ds = db.send(:metadata_dataset).clone(:sql=>"EXPLAIN #{select_sql}") rows = ds.all Sequel::PrettyTable.string(rows, ds.columns) end
HAVING requires GROUP BY on SQLite
# File lib/sequel/adapters/shared/sqlite.rb, line 591 def having(*cond) raise(InvalidOperation, "Can only specify a HAVING clause on a grouped dataset") unless @opts[:group] super end
Handle uniqueness violations when inserting, by using a specified resolution algorithm. With no options, uses INSERT OR REPLACE. SQLite supports the following conflict resolution algoriths: ROLLBACK, ABORT, FAIL, IGNORE and REPLACE.
Examples:
DB[:table].insert_conflict.insert(a: 1, b: 2) # INSERT OR IGNORE INTO TABLE (a, b) VALUES (1, 2) DB[:table].insert_conflict(:replace).insert(a: 1, b: 2) # INSERT OR REPLACE INTO TABLE (a, b) VALUES (1, 2)
# File lib/sequel/adapters/shared/sqlite.rb, line 625 def insert_conflict(resolution = :ignore) unless INSERT_CONFLICT_RESOLUTIONS.include?(resolution.to_s.upcase) raise Error, "Invalid value passed to Dataset#insert_conflict: #{resolution.inspect}. The allowed values are: :rollback, :abort, :fail, :ignore, or :replace" end clone(:insert_conflict => resolution) end
Ignore uniqueness/exclusion violations when inserting, using INSERT OR IGNORE. Exists mostly for compatibility to MySQL's insert_ignore. Example:
DB[:table].insert_ignore.insert(a: 1, b: 2) # INSERT OR IGNORE INTO TABLE (a, b) VALUES (1, 2)
# File lib/sequel/adapters/shared/sqlite.rb, line 637 def insert_ignore insert_conflict(:ignore) end
SQLite uses the nonstandard ` (backtick) for quoting identifiers.
# File lib/sequel/adapters/shared/sqlite.rb, line 597 def quoted_identifier_append(sql, c) sql << '`' << c.to_s.gsub('`', '``') << '`' end
When a qualified column is selected on SQLite and the qualifier is a subselect, the column name used is the full qualified name (including the qualifier) instead of just the column name. To get correct column names, you must use an alias.
# File lib/sequel/adapters/shared/sqlite.rb, line 605 def select(*cols) if ((f = @opts[:from]) && f.any?{|t| t.is_a?(Dataset) || (t.is_a?(SQL::AliasedExpression) && t.expression.is_a?(Dataset))}) || ((j = @opts[:join]) && j.any?{|t| t.table.is_a?(Dataset)}) super(*cols.map{|c| alias_qualified_column(c)}) else super end end
SQLite 3.8.3+ supports common table expressions.
# File lib/sequel/adapters/shared/sqlite.rb, line 642 def supports_cte?(type=:select) db.sqlite_version >= 30803 end
SQLite supports CTEs in subqueries if it supports CTEs.
# File lib/sequel/adapters/shared/sqlite.rb, line 647 def supports_cte_in_subqueries? supports_cte? end
SQLite does not support table aliases with column aliases
# File lib/sequel/adapters/shared/sqlite.rb, line 652 def supports_derived_column_lists? false end
SQLite does not support INTERSECT ALL or EXCEPT ALL
# File lib/sequel/adapters/shared/sqlite.rb, line 657 def supports_intersect_except_all? false end
SQLite does not support IS TRUE
# File lib/sequel/adapters/shared/sqlite.rb, line 662 def supports_is_true? false end
SQLite does not support multiple columns for the IN/NOT IN operators
# File lib/sequel/adapters/shared/sqlite.rb, line 667 def supports_multiple_column_in? false end
SQLite supports timezones in literal timestamps, since it stores them as text. But using timezones in timestamps breaks SQLite datetime functions, so we allow the user to override the default per database.
# File lib/sequel/adapters/shared/sqlite.rb, line 674 def supports_timestamp_timezones? db.use_timestamp_timezones? end
SQLite cannot use WHERE 't'.
# File lib/sequel/adapters/shared/sqlite.rb, line 679 def supports_where_true? false end
SQLite treats a DELETE with no WHERE clause as a TRUNCATE
# File lib/sequel/adapters/shared/sqlite.rb, line 786 def _truncate_sql(table) "DELETE FROM #{table}" end
If col is a qualified column, alias it to the same as the column name
# File lib/sequel/adapters/shared/sqlite.rb, line 694 def alias_qualified_column(col) case col when Symbol t, c, a = split_symbol(col) if t && !a alias_qualified_column(SQL::QualifiedIdentifier.new(t, c)) else col end when SQL::QualifiedIdentifier SQL::AliasedExpression.new(col, col.column) else col end end
SQLite uses string literals instead of identifiers in AS clauses.
# File lib/sequel/adapters/shared/sqlite.rb, line 686 def as_sql_append(sql, aliaz, column_aliases=nil) raise Error, "sqlite does not support derived column lists" if column_aliases aliaz = aliaz.value if aliaz.is_a?(SQL::Identifier) sql << ' AS ' literal_append(sql, aliaz.to_s) end
SQLite supports a maximum of 500 rows in a VALUES clause.
# File lib/sequel/adapters/shared/sqlite.rb, line 711 def default_import_slice 500 end
SQL fragment specifying a list of identifiers
# File lib/sequel/adapters/shared/sqlite.rb, line 716 def identifier_list(columns) columns.map{|i| quote_identifier(i)}.join(', ') end
Add OR clauses to SQLite INSERT statements
# File lib/sequel/adapters/shared/sqlite.rb, line 721 def insert_conflict_sql(sql) if resolution = @opts[:insert_conflict] sql << " OR " << resolution.to_s.upcase end end
SQLite uses a preceding X for hex escaping strings
# File lib/sequel/adapters/shared/sqlite.rb, line 728 def literal_blob_append(sql, v) sql << "X'" << v.unpack("H*").first << "'" end
Respect the database integer_booleans setting, using 0 or 'f'.
# File lib/sequel/adapters/shared/sqlite.rb, line 733 def literal_false @db.integer_booleans ? '0' : "'f'" end
Respect the database integer_booleans setting, using 1 or 't'.
# File lib/sequel/adapters/shared/sqlite.rb, line 738 def literal_true @db.integer_booleans ? '1' : "'t'" end
SQLite only supporting multiple rows in the VALUES clause starting in 3.7.11. On older versions, fallback to using a UNION.
# File lib/sequel/adapters/shared/sqlite.rb, line 744 def multi_insert_sql_strategy db.sqlite_version >= 30711 ? :values : :union end
Emulate the char_length function with length
# File lib/sequel/adapters/shared/sqlite.rb, line 749 def native_function_name(emulated_function) if emulated_function == :char_length 'length' else super end end
SQLite does not support FOR UPDATE, but silently ignore it instead of raising an error for compatibility with other databases.
# File lib/sequel/adapters/shared/sqlite.rb, line 760 def select_lock_sql(sql) super unless @opts[:lock] == :update end
# File lib/sequel/adapters/shared/sqlite.rb, line 764 def select_only_offset_sql(sql) sql << " LIMIT -1 OFFSET " literal_append(sql, @opts[:offset]) end
Support VALUES clause instead of the SELECT clause to return rows.
# File lib/sequel/adapters/shared/sqlite.rb, line 770 def select_values_sql(sql) sql << "VALUES " expression_list_append(sql, opts[:values]) end
SQLite does not support CTEs directly inside UNION/INTERSECT/EXCEPT.
# File lib/sequel/adapters/shared/sqlite.rb, line 776 def supports_cte_in_compounds? false end
SQLite supports quoted function names.
# File lib/sequel/adapters/shared/sqlite.rb, line 781 def supports_quoted_function_names? true end