Class: SQLite3::Database

Inherits:
Object
  • Object
show all
Includes:
Pragmas
Defined in:
lib/sqlite3/database.rb,
ext/sqlite3/database.c

Overview

The Database class encapsulates a single connection to a SQLite3 database. Its usage is very straightforward:

require 'sqlite3'

SQLite3::Database.new( "data.db" ) do |db|
  db.execute( "select * from table" ) do |row|
    p row
  end
end

It wraps the lower-level methods provides by the selected driver, and includes the Pragmas module for access to various pragma convenience methods.

The Database class provides type translation services as well, by which the SQLite3 data types (which are all represented as strings) may be converted into their corresponding types (as defined in the schemas for their tables). This translation only occurs when querying data from the database–insertions and updates are all still typeless.

Furthermore, the Database class has been designed to work well with the ArrayFields module from Ara Howard. If you require the ArrayFields module before performing a query, and if you have not enabled results as hashes, then the results will all be indexible by field name.

Defined Under Namespace

Classes: FunctionProxy

Constant Summary

Constants included from Pragmas

Pragmas::AUTO_VACUUM_MODES, Pragmas::ENCODINGS, Pragmas::JOURNAL_MODES, Pragmas::LOCKING_MODES, Pragmas::SYNCHRONOUS_MODES, Pragmas::TEMP_STORE_MODES, Pragmas::WAL_CHECKPOINTS

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Pragmas

#application_id, #application_id=, #auto_vacuum, #auto_vacuum=, #automatic_index, #automatic_index=, #cache_size, #cache_size=, #cache_spill, #cache_spill=, #case_sensitive_like=, #cell_size_check, #cell_size_check=, #checkpoint_fullfsync, #checkpoint_fullfsync=, #collation_list, #compile_options, #count_changes, #count_changes=, #data_version, #database_list, #default_cache_size, #default_cache_size=, #default_synchronous, #default_synchronous=, #default_temp_store, #default_temp_store=, #defer_foreign_keys, #defer_foreign_keys=, #encoding=, #foreign_key_check, #foreign_key_list, #foreign_keys, #foreign_keys=, #freelist_count, #full_column_names, #full_column_names=, #fullfsync, #fullfsync=, #get_boolean_pragma, #get_enum_pragma, #get_int_pragma, #get_query_pragma, #ignore_check_constraints=, #incremental_vacuum, #index_info, #index_list, #index_xinfo, #integrity_check, #journal_mode, #journal_mode=, #journal_size_limit, #journal_size_limit=, #legacy_file_format, #legacy_file_format=, #locking_mode, #locking_mode=, #max_page_count, #max_page_count=, #mmap_size, #mmap_size=, #page_count, #page_size, #page_size=, #parser_trace=, #query_only, #query_only=, #quick_check, #read_uncommitted, #read_uncommitted=, #recursive_triggers, #recursive_triggers=, #reverse_unordered_selects, #reverse_unordered_selects=, #schema_cookie, #schema_cookie=, #schema_version, #schema_version=, #secure_delete, #secure_delete=, #set_boolean_pragma, #set_enum_pragma, #set_int_pragma, #short_column_names, #short_column_names=, #shrink_memory, #soft_heap_limit, #soft_heap_limit=, #stats, #synchronous, #synchronous=, #table_info, #temp_store, #temp_store=, #threads, #threads=, #user_cookie, #user_cookie=, #user_version, #user_version=, #vdbe_addoptrace=, #vdbe_debug=, #vdbe_listing=, #vdbe_trace, #vdbe_trace=, #wal_autocheckpoint, #wal_autocheckpoint=, #wal_checkpoint, #wal_checkpoint=, #writable_schema=

Constructor Details

#initialize(file, options = {}, zvfs = nil) ⇒ Database

call-seq: SQLite3::Database.new(file, options = {})

Create a new Database object that opens the given file. If utf16 is true, the filename is interpreted as a UTF-16 encoded string.

By default, the new database will return result rows as arrays (#results_as_hash) and has type translation disabled (#type_translation=).



65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
 
# File 'lib/sqlite3/database.rb', line 65

def initialize file, options = {}, zvfs = nil
  mode = Constants::Open::READWRITE | Constants::Open::CREATE

  file = file.to_path if file.respond_to? :to_path
  if file.encoding == ::Encoding::UTF_16LE || file.encoding == ::Encoding::UTF_16BE || options[:utf16]
    open16 file
  else
    # The three primary flag values for sqlite3_open_v2 are:
    # SQLITE_OPEN_READONLY
    # SQLITE_OPEN_READWRITE
    # SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE -- always used for sqlite3_open and sqlite3_open16
    mode = Constants::Open::READONLY if options[:readonly]

    if options[:readwrite]
      raise "conflicting options: readonly and readwrite" if options[:readonly]
      mode = Constants::Open::READWRITE
    end

    if options[:flags]
      if options[:readonly] || options[:readwrite]
        raise "conflicting options: flags with readonly and/or readwrite"
      end
      mode = options[:flags]
    end

    open_v2 file.encode("utf-8"), mode, zvfs

    if options[:strict]
      disable_quirk_mode
    end
  end

  @tracefunc        = nil
  @authorizer       = nil
  @encoding         = nil
  @busy_handler     = nil
  @collations       = {}
  @functions        = {}
  @results_as_hash  = options[:results_as_hash]
  @type_translation = options[:type_translation]
  @type_translator  = make_type_translator @type_translation
  @readonly         = mode & Constants::Open::READONLY != 0

  if block_given?
    begin
      yield self
    ensure
      close
    end
  end
end

Instance Attribute Details

#collations ⇒ Object (readonly)

Returns the value of attribute collations.



36
37
38
 
# File 'lib/sqlite3/database.rb', line 36

def collations
  @collations
end

#results_as_hash ⇒ Object

A boolean that indicates whether rows in result sets should be returned as hashes or not. By default, rows are returned as arrays.



55
56
57
 
# File 'lib/sqlite3/database.rb', line 55

def results_as_hash
  @results_as_hash
end

#type_translation ⇒ Object

:nodoc:



124
125
126
 
# File 'lib/sqlite3/database.rb', line 124

def type_translation
  @type_translation
end

Class Method Details

.quote(string) ⇒ Object

Quotes the given string, making it safe to use in an SQL statement. It replaces all instances of the single-quote character with two single-quote characters. The modified string is returned.



47
48
49
 
# File 'lib/sqlite3/database.rb', line 47

def quote( string )
  string.gsub( /'/, "''" )
end

Instance Method Details

#authorizer(&block) ⇒ Object

Installs (or removes) a block that will be invoked for every access to the database. If the block returns 0 (or nil), the statement is allowed to proceed. Returning 1 causes an authorization error to occur, and returning 2 causes the access to be silently denied.



140
141
142
 
# File 'lib/sqlite3/database.rb', line 140

def authorizer( &block )
  self.authorizer = block
end

#set_authorizer=(auth) ⇒ Object

Set the authorizer for this database. auth must respond to call, and call must take 5 arguments.

Installs (or removes) a block that will be invoked for every access to the database. If the block returns 0 (or true), the statement is allowed to proceed. Returning 1 or false causes an authorization error to occur, and returning 2 or nil causes the access to be silently denied.



481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
 
# File 'ext/sqlite3/database.c', line 481

static VALUE set_authorizer(VALUE self, VALUE authorizer)
{
  sqlite3RubyPtr ctx;
  int status;

  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  status = sqlite3_set_authorizer(
      ctx->db, NIL_P(authorizer) ? NULL : rb_sqlite3_auth, (void *)self
  );

  CHECK(ctx->db, status);

  rb_iv_set(self, "@authorizer", authorizer);

  return self;
}

#busy_handler {|count| ... } ⇒ Object #busy_handler(Class.new{) ⇒ Object

Register a busy handler with this database instance. When a requested resource is busy, this handler will be invoked. If the handler returns false, the operation will be aborted; otherwise, the resource will be requested again.

The handler will be invoked with the name of the resource that was busy, and the number of times it has been retried.

See also the mutually exclusive #busy_timeout.

Overloads:

  • #busy_handler {|count| ... } ⇒ Object

    Yields:

    • (count) 


192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
 
# File 'ext/sqlite3/database.c', line 192

static VALUE busy_handler(int argc, VALUE *argv, VALUE self)
{
  sqlite3RubyPtr ctx;
  VALUE block;
  int status;

  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  rb_scan_args(argc, argv, "01", &block);

  if(NIL_P(block) && rb_block_given_p()) block = rb_block_proc();

  rb_iv_set(self, "@busy_handler", block);

  status = sqlite3_busy_handler(
      ctx->db, NIL_P(block) ? NULL : rb_sqlite3_busy_handler, (void *)self);

  CHECK(ctx->db, status);

  return self;
}

#busy_timeout=(ms) ⇒ Object Also known as: busy_timeout

Indicates that if a request for a resource terminates because that resource is busy, SQLite should sleep and retry for up to the indicated number of milliseconds. By default, SQLite does not retry busy resources. To restore the default behavior, send 0 as the ms parameter.

See also the mutually exclusive #busy_handler.



510
511
512
513
514
515
516
517
518
519
 
# File 'ext/sqlite3/database.c', line 510

static VALUE set_busy_timeout(VALUE self, VALUE timeout)
{
  sqlite3RubyPtr ctx;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  CHECK(ctx->db, sqlite3_busy_timeout(ctx->db, (int)NUM2INT(timeout)));

  return self;
}

#changes ⇒ Object

Returns the number of changes made to this database instance by the last operation performed. Note that a “delete from table” without a where clause will not affect this value.



438
439
440
441
442
443
444
445
 
# File 'ext/sqlite3/database.c', line 438

static VALUE changes(VALUE self)
{
  sqlite3RubyPtr ctx;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  return INT2NUM(sqlite3_changes(ctx->db));
}

#close ⇒ Object

Closes this database.



89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
 
# File 'ext/sqlite3/database.c', line 89

static VALUE sqlite3_rb_close(VALUE self)
{
  sqlite3RubyPtr ctx;
  sqlite3 * db;
  Data_Get_Struct(self, sqlite3Ruby, ctx);

  db = ctx->db;
  CHECK(db, sqlite3_close(ctx->db));

  ctx->db = NULL;

  rb_iv_set(self, "-aggregators", Qnil);

  return self;
}

#closed? ⇒ Boolean

Returns true if this database instance has been closed (see #close).

Returns:

  • (Boolean) 


109
110
111
112
113
114
115
116
117
 
# File 'ext/sqlite3/database.c', line 109

static VALUE closed_p(VALUE self)
{
  sqlite3RubyPtr ctx;
  Data_Get_Struct(self, sqlite3Ruby, ctx);

  if(!ctx->db) return Qtrue;

  return Qfalse;
}

#collation(name, comparator) ⇒ Object

Add a collation with name name, and a comparator object. The comparator object should implement a method called “compare” that takes two parameters and returns an integer less than, equal to, or greater than 0.



571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
 
# File 'ext/sqlite3/database.c', line 571

static VALUE collation(VALUE self, VALUE name, VALUE comparator)
{
  sqlite3RubyPtr ctx;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  CHECK(ctx->db, sqlite3_create_collation(
        ctx->db,
        StringValuePtr(name),
        SQLITE_UTF8,
        (void *)comparator,
        NIL_P(comparator) ? NULL : rb_comparator_func));

  /* Make sure our comparator doesn't get garbage collected. */
  rb_hash_aset(rb_iv_get(self, "@collations"), name, comparator);

  return self;
}

#commit ⇒ Object

Commits the current transaction. If there is no current transaction, this will cause an error to be raised. This returns true, in order to allow it to be used in idioms like abort? and rollback or commit.



644
645
646
647
 
# File 'lib/sqlite3/database.rb', line 644

def commit
  execute "commit transaction"
  true
end

#complete?(sql) ⇒ Boolean

Return true if the string is a valid (ie, parsable) SQL statement, and false otherwise.

Returns:

  • (Boolean) 


424
425
426
427
428
429
430
 
# File 'ext/sqlite3/database.c', line 424

static VALUE complete_p(VALUE UNUSED(self), VALUE sql)
{
  if(sqlite3_complete(StringValuePtr(sql)))
    return Qtrue;

  return Qfalse;
}

#create_aggregate(name, arity, step = nil, finalize = nil, text_rep = Constants::TextRep::ANY, &block) ⇒ Object

Creates a new aggregate function for use in SQL statements. Aggregate functions are functions that apply over every row in the result set, instead of over just a single row. (A very common aggregate function is the “count” function, for determining the number of rows that match a query.)

The new function will be added as name, with the given arity. (For variable arity functions, use -1 for the arity.)

The step parameter must be a proc object that accepts as its first parameter a FunctionProxy instance (representing the function invocation), with any subsequent parameters (up to the function’s arity). The step callback will be invoked once for each row of the result set.

The finalize parameter must be a proc object that accepts only a single parameter, the FunctionProxy instance representing the current function invocation. It should invoke FunctionProxy#result= to store the result of the function.

Example:

db.create_aggregate( "lengths", 1 ) do
  step do |func, value|
    func[ :total ] ||= 0
    func[ :total ] += ( value ? value.length : 0 )
  end

  finalize do |func|
    func.result = func[ :total ] || 0
  end
end

puts db.get_first_value( "select lengths(name) from table" )

See also #create_aggregate_handler for a more object-oriented approach to aggregate functions.



435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
 
# File 'lib/sqlite3/database.rb', line 435

def create_aggregate( name, arity, step=nil, finalize=nil,
  text_rep=Constants::TextRep::ANY, &block )

  proxy = Class.new do
    def self.step( &block )
      define_method(:step_with_ctx, &block)
    end

    def self.finalize( &block )
      define_method(:finalize_with_ctx, &block)
    end
  end

  if block_given?
    proxy.instance_eval(&block)
  else
    proxy.class_eval do
      define_method(:step_with_ctx, step)
      define_method(:finalize_with_ctx, finalize)
    end
  end

  proxy.class_eval do
    # class instance variables
    @name = name
    @arity = arity

    def self.name
      @name
    end

    def self.arity
      @arity
    end

    def initialize
      @ctx = FunctionProxy.new
    end

    def step( *args )
      step_with_ctx(@ctx, *args)
    end

    def finalize
      finalize_with_ctx(@ctx)
      @ctx.result
    end
  end
  define_aggregator2(proxy, name)
end

#create_aggregate_handler(handler) ⇒ Object

This is another approach to creating an aggregate function (see #create_aggregate). Instead of explicitly specifying the name, callbacks, arity, and type, you specify a factory object (the “handler”) that knows how to obtain all of that information. The handler should respond to the following messages:

arity

corresponds to the arity parameter of #create_aggregate. This message is optional, and if the handler does not respond to it, the function will have an arity of -1.

name

this is the name of the function. The handler must implement this message.

new

this must be implemented by the handler. It should return a new instance of the object that will handle a specific invocation of the function.

The handler instance (the object returned by the new message, described above), must respond to the following messages:

step

this is the method that will be called for each step of the aggregate function’s evaluation. It should implement the same signature as the step callback for #create_aggregate.

finalize

this is the method that will be called to finalize the aggregate function’s evaluation. It should implement the same signature as the finalize callback for #create_aggregate.

Example:

class LengthsAggregateHandler
  def self.arity; 1; end
  def self.name; 'lengths'; end

  def initialize
    @total = 0
  end

  def step( ctx, name )
    @total += ( name ? name.length : 0 )
  end

  def finalize( ctx )
    ctx.result = @total
  end
end

db.create_aggregate_handler( LengthsAggregateHandler )
puts db.get_first_value( "select lengths(name) from A" )



533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
 
# File 'lib/sqlite3/database.rb', line 533

def create_aggregate_handler( handler )
  # This is a compatibility shim so the (basically pointless) FunctionProxy
  # "ctx" object is passed as first argument to both step() and finalize().
  # Now its up to the library user whether he prefers to store his
  # temporaries as instance variables or fields in the FunctionProxy.
  # The library user still must set the result value with
  # FunctionProxy.result= as there is no backwards compatible way to
  # change this.
  proxy = Class.new(handler) do
    def initialize
      super
      @fp = FunctionProxy.new
    end

    def step( *args )
      super(@fp, *args)
    end

    def finalize
      super(@fp)
      @fp.result
    end
  end
  define_aggregator2(proxy, proxy.name)
  self
end

#create_function(name, arity, text_rep = Constants::TextRep::UTF8, &block) ⇒ Object

Creates a new function for use in SQL statements. It will be added as name, with the given arity. (For variable arity functions, use -1 for the arity.)

The block should accept at least one parameter–the FunctionProxy instance that wraps this function invocation–and any other arguments it needs (up to its arity).

The block does not return a value directly. Instead, it will invoke the FunctionProxy#result= method on the func parameter and indicate the return value that way.

Example:

db.create_function( "maim", 1 ) do |func, value|
  if value.nil?
    func.result = nil
  else
    func.result = value.split(//).sort.join
  end
end

puts db.get_first_value( "select maim(name) from table" )



390
391
392
393
394
395
396
397
 
# File 'lib/sqlite3/database.rb', line 390

def create_function name, arity, text_rep=Constants::TextRep::UTF8, &block
  define_function_with_flags(name, text_rep) do |*args|
    fp = FunctionProxy.new
    block.call(fp, *args)
    fp.result
  end
  self
end

#define_aggregator(name, aggregator) ⇒ Object

Define an aggregate function named name using a object template object aggregator. aggregator must respond to step and finalize. step will be called with row information and finalize must return the return value for the aggregator function.

_API Change:_ aggregator must also implement clone. The provided aggregator object will serve as template that is cloned to provide the individual instances of the aggregate function. Regular ruby objects already provide a suitable clone. The functions arity is the arity of the step method.



570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
 
# File 'lib/sqlite3/database.rb', line 570

def define_aggregator( name, aggregator )
  # Previously, this has been implemented in C. Now this is just yet
  # another compatibility shim
  proxy = Class.new do
    @template = aggregator
    @name = name

    def self.template
      @template
    end

    def self.name
      @name
    end

    def self.arity
      # this is what sqlite3_obj_method_arity did before
      @template.method(:step).arity
    end

    def initialize
      @klass = self.class.template.clone
    end

    def step(*args)
      @klass.step(*args)
    end

    def finalize
      @klass.finalize
    end
  end
  define_aggregator2(proxy, name)
  self
end

#define_function(name) {|args, ...| ... } ⇒ Object

Define a function named name with args. The arity of the block will be used as the arity for the function defined.

Yields:

  • (args, ...) 


371
372
373
374
 
# File 'ext/sqlite3/database.c', line 371

static VALUE define_function(VALUE self, VALUE name)
{
  return define_function_with_flags(self, name, INT2FIX(SQLITE_UTF8));
}

#define_function_with_flags(name, flags) {|args, ...| ... } ⇒ Object

Define a function named name with args using TextRep bitflags flags. The arity of the block will be used as the arity for the function defined.

Yields:

  • (args, ...) 


337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
 
# File 'ext/sqlite3/database.c', line 337

static VALUE define_function_with_flags(VALUE self, VALUE name, VALUE flags)
{
  sqlite3RubyPtr ctx;
  VALUE block;
  int status;

  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  block = rb_block_proc();

  status = sqlite3_create_function(
    ctx->db,
    StringValuePtr(name),
    rb_proc_arity(block),
    NUM2INT(flags),
    (void *)block,
    rb_sqlite3_func,
    NULL,
    NULL
  );

  CHECK(ctx->db, status);

  rb_hash_aset(rb_iv_get(self, "@functions"), name, block);

  return self;
}

#enable_load_extension(onoff) ⇒ Object

Enable or disable extension loading.



623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
 
# File 'ext/sqlite3/database.c', line 623

static VALUE enable_load_extension(VALUE self, VALUE onoff)
{
  sqlite3RubyPtr ctx;
  int onoffparam;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  if (Qtrue == onoff) {
    onoffparam = 1;
  } else if (Qfalse == onoff) {
    onoffparam = 0;
  } else {
    onoffparam = (int)NUM2INT(onoff);
  }

  CHECK(ctx->db, sqlite3_enable_load_extension(ctx->db, onoffparam));

  return self;
}

#encoding ⇒ Object

Fetch the encoding set on this database



659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
 
# File 'ext/sqlite3/database.c', line 659

static VALUE db_encoding(VALUE self)
{
  sqlite3RubyPtr ctx;
  VALUE enc;

  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  enc = rb_iv_get(self, "@encoding");

  if(NIL_P(enc)) {
    sqlite3_exec(ctx->db, "PRAGMA encoding", enc_cb, (void *)self, NULL);
  }

  return rb_iv_get(self, "@encoding");
}

#errcode ⇒ Object

Return an integer representing the last error to have occurred with this database.



410
411
412
413
414
415
416
417
 
# File 'ext/sqlite3/database.c', line 410

static VALUE errcode_(VALUE self)
{
  sqlite3RubyPtr ctx;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  return INT2NUM(sqlite3_errcode(ctx->db));
}

#errmsg ⇒ Object

Return a string describing the last error to have occurred with this database.



396
397
398
399
400
401
402
403
 
# File 'ext/sqlite3/database.c', line 396

static VALUE errmsg(VALUE self)
{
  sqlite3RubyPtr ctx;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  return rb_str_new2(sqlite3_errmsg(ctx->db));
}

#execute(sql, bind_vars = [], *args, &block) ⇒ Object

Executes the given SQL statement. If additional parameters are given, they are treated as bind variables, and are bound to the placeholders in the query.

Note that if any of the values passed to this are hashes, then the key/value pairs are each bound separately, with the key being used as the name of the placeholder to bind the value to.

The block is optional. If given, it will be invoked for each row returned by the query. Otherwise, any results are accumulated into an array and returned wholesale.

See also #execute2, #query, and #execute_batch for additional ways of executing statements.



181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
 
# File 'lib/sqlite3/database.rb', line 181

def execute sql, bind_vars = [], *args, &block
  if bind_vars.nil? || !args.empty?
    if args.empty?
      bind_vars = []
    else
      bind_vars = [bind_vars] + args
    end

    warn(<<-eowarn) if $VERBOSE
#{caller[0]} is calling `SQLite3::Database#execute` with nil or multiple bind params without using an array.  Please switch to passing bind parameters as an array. Support for bind parameters as *args will be removed in 2.0.0.
    eowarn
  end

  prepare( sql ) do |stmt|
    stmt.bind_params(bind_vars)
    stmt    = ResultSet.new self, stmt

    if block_given?
      stmt.each do |row|
        yield row
      end
    else
      stmt.to_a
    end
  end
end

#execute2(sql, *bind_vars) ⇒ Object

Executes the given SQL statement, exactly as with #execute. However, the first row returned (either via the block, or in the returned array) is always the names of the columns. Subsequent rows correspond to the data from the result set.

Thus, even if the query itself returns no rows, this method will always return at least one row–the names of the columns.

See also #execute, #query, and #execute_batch for additional ways of executing statements.



218
219
220
221
222
223
224
225
226
227
228
229
 
# File 'lib/sqlite3/database.rb', line 218

def execute2( sql, *bind_vars )
  prepare( sql ) do |stmt|
    result = stmt.execute( *bind_vars )
    if block_given?
      yield stmt.columns
      result.each { |row| yield row }
    else
      return result.inject( [ stmt.columns ] ) { |arr,row|
        arr << row; arr }
    end
  end
end

#execute_batch(sql, bind_vars = [], *args) ⇒ Object

Executes all SQL statements in the given string. By contrast, the other means of executing queries will only execute the first statement in the string, ignoring all subsequent statements. This will execute each one in turn. The same bind parameters, if given, will be applied to each statement.

This always returns nil, making it unsuitable for queries that return rows.

See also #execute_batch2 for additional ways of executing statements.



242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
 
# File 'lib/sqlite3/database.rb', line 242

def execute_batch( sql, bind_vars = [], *args )
  # FIXME: remove this stuff later
  unless [Array, Hash].include?(bind_vars.class)
    bind_vars = [bind_vars]
    warn(<<-eowarn) if $VERBOSE
#{caller[0]} is calling `SQLite3::Database#execute_batch` with bind parameters that are not a list of a hash.  Please switch to passing bind parameters as an array or hash. Support for this behavior will be removed in version 2.0.0.
    eowarn
  end

  # FIXME: remove this stuff later
  if bind_vars.nil? || !args.empty?
    if args.empty?
      bind_vars = []
    else
      bind_vars = [nil] + args
    end

    warn(<<-eowarn) if $VERBOSE
#{caller[0]} is calling `SQLite3::Database#execute_batch` with nil or multiple bind params without using an array.  Please switch to passing bind parameters as an array. Support for this behavior will be removed in version 2.0.0.
    eowarn
  end

  sql = sql.strip
  until sql.empty? do
    prepare( sql ) do |stmt|
      unless stmt.closed?
        # FIXME: this should probably use sqlite3's api for batch execution
        # This implementation requires stepping over the results.
        if bind_vars.length == stmt.bind_parameter_count
          stmt.bind_params(bind_vars)
        end
        stmt.step
      end
      sql = stmt.remainder.strip
    end
  end
  # FIXME: we should not return `nil` as a success return value
  nil
end

#execute_batch2(sql, &block) ⇒ Object

Executes all SQL statements in the given string. By contrast, the other means of executing queries will only execute the first statement in the string, ignoring all subsequent statements. This will execute each one in turn. Bind parameters cannot be passed to #execute_batch2.

If a query is made, all values will be returned as strings. If no query is made, an empty array will be returned.

Because all values except for ‘NULL’ are returned as strings, a block can be passed to parse the values accordingly.

See also #execute_batch for additional ways of executing statements.



295
296
297
298
299
300
301
302
303
304
 
# File 'lib/sqlite3/database.rb', line 295

def execute_batch2(sql, &block)
  if block_given?
    result = exec_batch(sql, @results_as_hash)
    result.map do |val|
      yield val
    end
  else
    exec_batch(sql, @results_as_hash)
  end
end

#extended_result_codes=(true) ⇒ Object

Enable extended result codes in SQLite. These result codes allow for more detailed exception reporting, such a which type of constraint is violated.



526
527
528
529
530
531
532
533
534
535
 
# File 'ext/sqlite3/database.c', line 526

static VALUE set_extended_result_codes(VALUE self, VALUE enable)
{
  sqlite3RubyPtr ctx;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  CHECK(ctx->db, sqlite3_extended_result_codes(ctx->db, RTEST(enable) ? 1 : 0));

  return self;
}

#filename(db_name = 'main') ⇒ Object

Returns the filename for the database named db_name. db_name defaults to “main”. Main return ‘nil` or an empty string if the database is temporary or in-memory.



163
164
165
 
# File 'lib/sqlite3/database.rb', line 163

def filename db_name = 'main'
  db_filename db_name
end

#get_first_row(sql, *bind_vars) ⇒ Object

A convenience method for obtaining the first row of a result set, and discarding all others. It is otherwise identical to #execute.

See also #get_first_value.



347
348
349
 
# File 'lib/sqlite3/database.rb', line 347

def get_first_row( sql, *bind_vars )
  execute( sql, *bind_vars ).first
end

#get_first_value(sql, *bind_vars) ⇒ Object

A convenience method for obtaining the first value of the first row of a result set, and discarding all other values and rows. It is otherwise identical to #execute.

See also #get_first_row.



356
357
358
359
360
361
362
363
 
# File 'lib/sqlite3/database.rb', line 356

def get_first_value( sql, *bind_vars )
  query( sql, bind_vars ) do |rs|
    if (row = rs.next)
      return @results_as_hash ? row[rs.columns[0]] : row[0]
    end
  end
  nil
end

#interrupt ⇒ Object

Interrupts the currently executing operation, causing it to abort.



380
381
382
383
384
385
386
387
388
389
 
# File 'ext/sqlite3/database.c', line 380

static VALUE interrupt(VALUE self)
{
  sqlite3RubyPtr ctx;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  sqlite3_interrupt(ctx->db);

  return self;
}

#last_insert_row_id ⇒ Object

Obtains the unique row ID of the last row to be inserted by this Database instance.



220
221
222
223
224
225
226
227
 
# File 'ext/sqlite3/database.c', line 220

static VALUE last_insert_row_id(VALUE self)
{
  sqlite3RubyPtr ctx;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  return LL2NUM(sqlite3_last_insert_rowid(ctx->db));
}

#load_extension(file) ⇒ Object

Loads an SQLite extension library from the named file. Extension loading must be enabled using db.enable_load_extension(true) prior to calling this API.



597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
 
# File 'ext/sqlite3/database.c', line 597

static VALUE load_extension(VALUE self, VALUE file)
{
  sqlite3RubyPtr ctx;
  int status;
  char *errMsg;
  VALUE errexp;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  status = sqlite3_load_extension(ctx->db, StringValuePtr(file), 0, &errMsg);
  if (status != SQLITE_OK)
  {
    errexp = rb_exc_new2(rb_eRuntimeError, errMsg);
    sqlite3_free(errMsg);
    rb_exc_raise(errexp);
  }

  return self;
}

#prepare(sql) ⇒ Object

Returns a Statement object representing the given SQL. This does not execute the statement; it merely prepares the statement for execution.

The Statement can then be executed using Statement#execute.



149
150
151
152
153
154
155
156
157
158
 
# File 'lib/sqlite3/database.rb', line 149

def prepare sql
  stmt = SQLite3::Statement.new( self, sql )
  return stmt unless block_given?

  begin
    yield stmt
  ensure
    stmt.close unless stmt.closed?
  end
end

#query(sql, bind_vars = [], *args) ⇒ Object

This is a convenience method for creating a statement, binding parameters to it, and calling execute:

result = db.query( "select * from foo where a=?", [5])
# is the same as
result = db.prepare( "select * from foo where a=?" ).execute( 5 )

You must be sure to call close on the ResultSet instance that is returned, or you could have problems with locks on the table. If called with a block, close will be invoked implicitly when the block terminates.



317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
 
# File 'lib/sqlite3/database.rb', line 317

def query( sql, bind_vars = [], *args )

  if bind_vars.nil? || !args.empty?
    if args.empty?
      bind_vars = []
    else
      bind_vars = [bind_vars] + args
    end

    warn(<<-eowarn) if $VERBOSE
#{caller[0]} is calling `SQLite3::Database#query` with nil or multiple bind params without using an array.  Please switch to passing bind parameters as an array. Support for this will be removed in version 2.0.0.
    eowarn
  end

  result = prepare( sql ).execute( bind_vars )
  if block_given?
    begin
      yield result
    ensure
      result.close
    end
  else
    return result
  end
end

#readonly? ⇒ Boolean

Returns true if the database has been open in readonly mode A helper to check before performing any operation

Returns:

  • (Boolean) 


660
661
662
 
# File 'lib/sqlite3/database.rb', line 660

def readonly?
  @readonly
end

#rollback ⇒ Object

Rolls the current transaction back. If there is no current transaction, this will cause an error to be raised. This returns true, in order to allow it to be used in idioms like abort? and rollback or commit.



653
654
655
656
 
# File 'lib/sqlite3/database.rb', line 653

def rollback
  execute "rollback transaction"
  true
end

#total_changes ⇒ Object

Returns the total number of changes made to this database instance since it was opened.



124
125
126
127
128
129
130
131
 
# File 'ext/sqlite3/database.c', line 124

static VALUE total_changes(VALUE self)
{
  sqlite3RubyPtr ctx;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  return INT2NUM(sqlite3_total_changes(ctx->db));
}

#trace {|sql| ... } ⇒ Object #trace(Class.new{) ⇒ Object

Installs (or removes) a block that will be invoked for every SQL statement executed. The block receives one parameter: the SQL statement executed. If the block is nil, any existing tracer will be uninstalled.

Overloads:

  • #trace {|sql| ... } ⇒ Object

    Yields:

    • (sql) 


148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
 
# File 'ext/sqlite3/database.c', line 148

static VALUE trace(int argc, VALUE *argv, VALUE self)
{
  sqlite3RubyPtr ctx;
  VALUE block;

  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  rb_scan_args(argc, argv, "01", &block);

  if(NIL_P(block) && rb_block_given_p()) block = rb_block_proc();

  rb_iv_set(self, "@tracefunc", block);

  sqlite3_trace(ctx->db, NIL_P(block) ? NULL : tracefunc, (void *)self);

  return self;
}

#transaction(mode = :deferred) ⇒ Object

Begins a new transaction. Note that nested transactions are not allowed by SQLite, so attempting to nest a transaction will result in a runtime exception.

The mode parameter may be either :deferred (the default), :immediate, or :exclusive.

If a block is given, the database instance is yielded to it, and the transaction is committed when the block terminates. If the block raises an exception, a rollback will be performed instead. Note that if a block is given, #commit and #rollback should never be called explicitly or you’ll get an error when the block terminates.

If a block is not given, it is the caller’s responsibility to end the transaction explicitly, either by calling #commit, or by calling #rollback.



622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
 
# File 'lib/sqlite3/database.rb', line 622

def transaction( mode = :deferred )
  execute "begin #{mode.to_s} transaction"

  if block_given?
    abort = false
    begin
      yield self
    rescue
      abort = true
      raise
    ensure
      abort and rollback or commit
    end
  end

  true
end

#transaction_active? ⇒ Boolean

Returns true if there is a transaction active, and false otherwise.

Returns:

  • (Boolean) 


681
682
683
684
685
686
687
688
 
# File 'ext/sqlite3/database.c', line 681

static VALUE transaction_active_p(VALUE self)
{
  sqlite3RubyPtr ctx;
  Data_Get_Struct(self, sqlite3Ruby, ctx);
  REQUIRE_OPEN_DB(ctx);

  return sqlite3_get_autocommit(ctx->db) ? Qfalse : Qtrue;
}

#translate_from_db(types, row) ⇒ Object

Translates a row of data from the database with the given types



711
712
713
 
# File 'lib/sqlite3/database.rb', line 711

def translate_from_db types, row
  @type_translator.call types, row
end

#translator ⇒ Object

Return the type translator employed by this database instance. Each database instance has its own type translator; this allows for different type handlers to be installed in each instance without affecting other instances. Furthermore, the translators are instantiated lazily, so that if a database does not use type translation, it will not be burdened by the overhead of a useless type translator. (See the Translator class.)



132
133
134
 
# File 'lib/sqlite3/database.rb', line 132

def translator
  @translator ||= Translator.new
end