Class: SQLite3::Database
- Inherits:
-
Object
- Object
- SQLite3::Database
- 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 provided 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.
Thread safety:
When ‘SQLite3.threadsafe?` returns true, it is safe to share instances of the database class among threads without adding specific locking. Other object instances may require applications to provide their own locks if they are to be shared among threads. Please see the README.md for more information.
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
-
#collations ⇒ Object
readonly
Returns the value of attribute collations.
-
#results_as_hash ⇒ Object
A boolean that indicates whether rows in result sets should be returned as hashes or not.
Class Method Summary collapse
-
.open(*args) ⇒ Object
Without block works exactly as new.
-
.quote(string) ⇒ Object
Quotes the given string, making it safe to use in an SQL statement.
Instance Method Summary collapse
-
#authorizer(&block) ⇒ Object
Installs (or removes) a block that will be invoked for every access to the database.
-
#set_authorizer=(auth) ⇒ Object
Set the authorizer for this database.
-
#build_result_set(stmt) ⇒ Object
Given a statement, return a result set.
-
#busy_handler(*args) ⇒ Object
Register a busy handler with this database instance.
-
#busy_handler_timeout=(milliseconds) ⇒ Object
Sets a #busy_handler that releases the GVL between retries, but only retries up to the indicated number of
milliseconds
. -
#busy_timeout=(ms) ⇒ Object
(also: #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.
-
#changes ⇒ Object
Returns the number of changes made to this database instance by the last operation performed.
-
#close ⇒ Object
Closes this database.
-
#closed? ⇒ Boolean
Returns
true
if this database instance has been closed (see #close). -
#collation(name, comparator) ⇒ Object
Add a collation with name
name
, and acomparator
object. -
#commit ⇒ Object
Commits the current transaction.
-
#complete?(sql) ⇒ Boolean
Return
true
if the string is a valid (ie, parsable) SQL statement, andfalse
otherwise. -
#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.
-
#create_aggregate_handler(handler) ⇒ Object
This is another approach to creating an aggregate function (see #create_aggregate).
-
#create_function(name, arity, text_rep = Constants::TextRep::UTF8, &block) ⇒ Object
Creates a new function for use in SQL statements.
-
#define_aggregator(name, aggregator) ⇒ Object
Define an aggregate function named
name
using a object template objectaggregator
. -
#define_function(name) {|args, ...| ... } ⇒ Object
Define a function named
name
withargs
. -
#define_function_with_flags(name, flags) {|args, ...| ... } ⇒ Object
Define a function named
name
withargs
using TextRep bitflagsflags
. -
#enable_load_extension(onoff) ⇒ Object
Enable or disable extension loading.
-
#encoding ⇒ Object
call-seq: db.encoding.
-
#errcode ⇒ Object
Return an integer representing the last error to have occurred with this database.
-
#errmsg ⇒ Object
Return a string describing the last error to have occurred with this database.
-
#execute(sql, bind_vars = [], &block) ⇒ Object
Executes the given SQL statement.
-
#execute2(sql, *bind_vars) ⇒ Object
Executes the given SQL statement, exactly as with #execute.
-
#execute_batch(sql, bind_vars = []) ⇒ Object
Executes all SQL statements in the given string.
-
#execute_batch2(sql, &block) ⇒ Object
Executes all SQL statements in the given string.
-
#extended_result_codes=(true) ⇒ Object
Enable extended result codes in SQLite.
-
#filename(db_name = "main") ⇒ Object
Returns the filename for the database named
db_name
. -
#get_first_row(sql, *bind_vars) ⇒ Object
A convenience method for obtaining the first row of a result set, and discarding all others.
-
#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.
-
#initialize(file, options = {}, zvfs = nil) ⇒ Database
constructor
call-seq: SQLite3::Database.new(file, options = {}).
-
#interrupt ⇒ Object
Interrupts the currently executing operation, causing it to abort.
-
#last_insert_row_id ⇒ Object
Obtains the unique row ID of the last row to be inserted by this Database instance.
-
#load_extension(file) ⇒ Object
Loads an SQLite extension library from the named file.
-
#prepare(sql) ⇒ Object
Returns a Statement object representing the given SQL.
-
#query(sql, bind_vars = []) ⇒ Object
This is a convenience method for creating a statement, binding parameters to it, and calling execute:.
-
#readonly? ⇒ Boolean
Returns
true
if the database has been open in readonly mode A helper to check before performing any operation. -
#rollback ⇒ Object
Rolls the current transaction back.
-
#statement_timeout=(ms) ⇒ Object
Indicates that if a query lasts longer than the indicated number of milliseconds, SQLite should interrupt that query and return an error.
-
#total_changes ⇒ Object
Returns the total number of changes made to this database instance since it was opened.
-
#trace(*args) ⇒ Object
Installs (or removes) a block that will be invoked for every SQL statement executed.
-
#transaction(mode = nil) ⇒ Object
Begins a new transaction.
-
#transaction_active? ⇒ Boolean
Returns
true
if there is a transaction active, andfalse
otherwise.
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.
Supported permissions options
:
-
the default mode is
READWRITE | CREATE
-
:readonly
: boolean (default false), true to set the mode toREADONLY
-
:readwrite
: boolean (default false), true to set the mode toREADWRITE
-
:flags
: set the mode to a combination of SQLite3::Constants::Open flags.
Supported encoding options
:
-
:utf16
: boolean (default false), is the filename’s encoding UTF-16 (only needed if the filename encoding is not UTF_16LE or BE)
Other supported options
:
-
:strict
: boolean (default false), disallow the use of double-quoted string literals (see www.sqlite.org/quirks.html#double_quoted_string_literals_are_accepted) -
:results_as_hash
: boolean (default false), return rows as hashes instead of arrays -
:default_transaction_mode
: one of:deferred
(default),:immediate
, or:exclusive
. If a mode is not specified in a call to #transaction, this will be the default transaction mode.
94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 |
# File 'lib/sqlite3/database.rb', line 94 def initialize file, = {}, 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 || [: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 [:readonly] if [:readwrite] raise "conflicting options: readonly and readwrite" if [:readonly] mode = Constants::Open::READWRITE end if [:flags] if [:readonly] || [:readwrite] raise "conflicting options: flags with readonly and/or readwrite" end mode = [:flags] end open_v2 file.encode("utf-8"), mode, zvfs if [:strict] disable_quirk_mode end end @tracefunc = nil @authorizer = nil @busy_handler = nil @progress_handler = nil @collations = {} @functions = {} @results_as_hash = [:results_as_hash] @readonly = mode & Constants::Open::READONLY != 0 @default_transaction_mode = [:default_transaction_mode] || :deferred if block_given? begin yield self ensure close end end end |
Instance Attribute Details
#collations ⇒ Object (readonly)
Returns the value of attribute collations.
42 43 44 |
# File 'lib/sqlite3/database.rb', line 42 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.
74 75 76 |
# File 'lib/sqlite3/database.rb', line 74 def results_as_hash @results_as_hash end |
Class Method Details
.open(*args) ⇒ Object
Without block works exactly as new. With block, like new closes the database at the end, but unlike new returns the result of the block instead of the database instance.
50 51 52 53 54 55 56 57 58 59 60 61 62 |
# File 'lib/sqlite3/database.rb', line 50 def open(*args) database = new(*args) if block_given? begin yield database ensure database.close end else database end end |
.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.
67 68 69 |
# File 'lib/sqlite3/database.rb', line 67 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.
156 157 158 |
# File 'lib/sqlite3/database.rb', line 156 def (&block) self. = 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.
582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 |
# File 'ext/sqlite3/database.c', line 582
static VALUE
set_authorizer(VALUE self, VALUE authorizer)
{
sqlite3RubyPtr ctx;
int status;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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;
}
|
#build_result_set(stmt) ⇒ Object
Given a statement, return a result set. This is not intended for general consumption :nodoc:
693 694 695 696 697 698 699 |
# File 'lib/sqlite3/database.rb', line 693 def build_result_set stmt if results_as_hash HashResultSet.new(self, stmt) else ResultSet.new(self, stmt) end end |
#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.
236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 |
# File 'ext/sqlite3/database.c', line 236
static VALUE
busy_handler(int argc, VALUE *argv, VALUE self)
{
sqlite3RubyPtr ctx;
VALUE block;
int status;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, ctx);
REQUIRE_OPEN_DB(ctx);
rb_scan_args(argc, argv, "01", &block);
if (NIL_P(block) && rb_block_given_p()) { block = rb_block_proc(); }
ctx->busy_handler = block;
status = sqlite3_busy_handler(
ctx->db,
NIL_P(block) ? NULL : rb_sqlite3_busy_handler,
(void *)ctx
);
CHECK(ctx->db, status);
return self;
}
|
#busy_handler_timeout=(milliseconds) ⇒ Object
Sets a #busy_handler that releases the GVL between retries, but only retries up to the indicated number of milliseconds
. This is an alternative to #busy_timeout, which holds the GVL while SQLite sleeps and retries.
642 643 644 645 646 647 648 649 650 651 652 653 654 655 |
# File 'lib/sqlite3/database.rb', line 642 def busy_handler_timeout=(milliseconds) timeout_seconds = milliseconds.fdiv(1000) busy_handler do |count| now = Process.clock_gettime(Process::CLOCK_MONOTONIC) if count.zero? @timeout_deadline = now + timeout_seconds elsif now > @timeout_deadline next false else sleep(0.001) end end end |
#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.
612 613 614 615 616 617 618 619 620 621 622 |
# File 'ext/sqlite3/database.c', line 612
static VALUE
set_busy_timeout(VALUE self, VALUE timeout)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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.
537 538 539 540 541 542 543 544 545 |
# File 'ext/sqlite3/database.c', line 537
static VALUE
changes(VALUE self)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, ctx);
REQUIRE_OPEN_DB(ctx);
return INT2NUM(sqlite3_changes(ctx->db));
}
|
#close ⇒ Object
Closes this database.
126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 |
# File 'ext/sqlite3/database.c', line 126
static VALUE
sqlite3_rb_close(VALUE self)
{
sqlite3RubyPtr ctx;
sqlite3 *db;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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).
147 148 149 150 151 152 153 154 155 156 |
# File 'ext/sqlite3/database.c', line 147
static VALUE
closed_p(VALUE self)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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.
676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 |
# File 'ext/sqlite3/database.c', line 676
static VALUE
collation(VALUE self, VALUE name, VALUE comparator)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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
.
618 619 620 621 |
# File 'lib/sqlite3/database.rb', line 618 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.
521 522 523 524 525 526 527 528 529 |
# File 'ext/sqlite3/database.c', line 521
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.
406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 |
# File 'lib/sqlite3/database.rb', line 406 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 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" )
504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 |
# File 'lib/sqlite3/database.rb', line 504 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" )
361 362 363 364 365 366 367 368 |
# File 'lib/sqlite3/database.rb', line 361 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.
541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 |
# File 'lib/sqlite3/database.rb', line 541 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.
464 465 466 467 468 |
# File 'ext/sqlite3/database.c', line 464
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.
429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 |
# File 'ext/sqlite3/database.c', line 429
static VALUE
define_function_with_flags(VALUE self, VALUE name, VALUE flags)
{
sqlite3RubyPtr ctx;
VALUE block;
int status;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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.
726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 |
# File 'ext/sqlite3/database.c', line 726
static VALUE
enable_load_extension(VALUE self, VALUE onoff)
{
sqlite3RubyPtr ctx;
int onoffparam;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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
call-seq: db.encoding
Fetch the encoding set on this database
148 149 150 |
# File 'lib/sqlite3/database.rb', line 148 def encoding prepare("PRAGMA encoding") { |stmt| Encoding.find(stmt.first.first) } end |
#errcode ⇒ Object
Return an integer representing the last error to have occurred with this database.
506 507 508 509 510 511 512 513 514 |
# File 'ext/sqlite3/database.c', line 506
static VALUE
errcode_(VALUE self)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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.
491 492 493 494 495 496 497 498 499 |
# File 'ext/sqlite3/database.c', line 491
static VALUE
errmsg(VALUE self)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, ctx);
REQUIRE_OPEN_DB(ctx);
return rb_str_new2(sqlite3_errmsg(ctx->db));
}
|
#execute(sql, bind_vars = [], &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.
197 198 199 200 201 202 203 204 205 206 207 208 209 210 |
# File 'lib/sqlite3/database.rb', line 197 def execute sql, bind_vars = [], &block prepare(sql) do |stmt| stmt.bind_params(bind_vars) stmt = build_result_set stmt if block stmt.each do |row| yield row end else stmt.to_a.freeze 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.
222 223 224 225 226 227 228 229 230 231 232 233 234 |
# File 'lib/sqlite3/database.rb', line 222 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.each_with_object([stmt.columns]) { |row, arr| arr << row } end end end |
#execute_batch(sql, bind_vars = []) ⇒ 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 the result of the last statement.
See also #execute_batch2 for additional ways of executing statements.
246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 |
# File 'lib/sqlite3/database.rb', line 246 def execute_batch(sql, bind_vars = []) sql = sql.strip result = nil until sql.empty? 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 result = stmt.step end sql = stmt.remainder.strip end end result 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.
279 280 281 282 283 284 285 286 287 288 |
# File 'lib/sqlite3/database.rb', line 279 def execute_batch2(sql, &block) if block 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.
629 630 631 632 633 634 635 636 637 638 639 |
# File 'ext/sqlite3/database.c', line 629
static VALUE
set_extended_result_codes(VALUE self, VALUE enable)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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.
179 180 181 |
# File 'lib/sqlite3/database.rb', line 179 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.
318 319 320 |
# File 'lib/sqlite3/database.rb', line 318 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.
327 328 329 330 331 332 333 334 |
# File 'lib/sqlite3/database.rb', line 327 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.
474 475 476 477 478 479 480 481 482 483 484 |
# File 'ext/sqlite3/database.c', line 474
static VALUE
interrupt(VALUE self)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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.
305 306 307 308 309 310 311 312 313 |
# File 'ext/sqlite3/database.c', line 305
static VALUE
last_insert_row_id(VALUE self)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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.
703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 |
# File 'ext/sqlite3/database.c', line 703
static VALUE
load_extension(VALUE self, VALUE file)
{
sqlite3RubyPtr ctx;
int status;
char *errMsg;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, ctx);
REQUIRE_OPEN_DB(ctx);
status = sqlite3_load_extension(ctx->db, StringValuePtr(file), 0, &errMsg);
CHECK_MSG(ctx->db, status, errMsg);
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.
165 166 167 168 169 170 171 172 173 174 |
# File 'lib/sqlite3/database.rb', line 165 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 = []) ⇒ 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.
301 302 303 304 305 306 307 308 309 310 311 312 |
# File 'lib/sqlite3/database.rb', line 301 def query(sql, bind_vars = []) result = prepare(sql).execute(bind_vars) if block_given? begin yield result ensure result.close end else result end end |
#readonly? ⇒ Boolean
Returns true
if the database has been open in readonly mode A helper to check before performing any operation
634 635 636 |
# File 'lib/sqlite3/database.rb', line 634 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
.
627 628 629 630 |
# File 'lib/sqlite3/database.rb', line 627 def rollback execute "rollback transaction" true end |
#statement_timeout=(ms) ⇒ Object
Indicates that if a query lasts longer than the indicated number of milliseconds, SQLite should interrupt that query and return an error. By default, SQLite does not interrupt queries. To restore the default behavior, send 0 as the ms
parameter.
286 287 288 289 290 291 292 293 294 295 296 297 298 |
# File 'ext/sqlite3/database.c', line 286
static VALUE
set_statement_timeout(VALUE self, VALUE milliseconds)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, ctx);
ctx->stmt_timeout = NUM2INT(milliseconds);
int n = NUM2INT(milliseconds) == 0 ? -1 : 1000;
sqlite3_progress_handler(ctx->db, n, rb_sqlite3_statement_timeout, (void *)ctx);
return self;
}
|
#total_changes ⇒ Object
Returns the total number of changes made to this database instance since it was opened.
163 164 165 166 167 168 169 170 171 |
# File 'ext/sqlite3/database.c', line 163
static VALUE
total_changes(VALUE self)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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.
189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 |
# File 'ext/sqlite3/database.c', line 189
static VALUE
trace(int argc, VALUE *argv, VALUE self)
{
sqlite3RubyPtr ctx;
VALUE block;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, 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 = nil) ⇒ 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
, :immediate
, or :exclusive
. If ‘nil` is specified, the default transaction mode, which was passed to #initialize, is used.
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.
595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 |
# File 'lib/sqlite3/database.rb', line 595 def transaction(mode = nil) mode = @default_transaction_mode if mode.nil? execute "begin #{mode} transaction" if block_given? abort = false begin yield self rescue abort = true raise ensure abort and rollback or commit end else true end end |
#transaction_active? ⇒ Boolean
Returns true
if there is a transaction active, and false
otherwise.
753 754 755 756 757 758 759 760 761 |
# File 'ext/sqlite3/database.c', line 753
static VALUE
transaction_active_p(VALUE self)
{
sqlite3RubyPtr ctx;
TypedData_Get_Struct(self, sqlite3Ruby, &database_type, ctx);
REQUIRE_OPEN_DB(ctx);
return sqlite3_get_autocommit(ctx->db) ? Qfalse : Qtrue;
}
|