Class: SQLite3::Database

### Home Classes Methods

### In Files

- lib/sqlite3/database.rb
- ext/sqlite3/backup.c

### Parent

Object

### Namespace

- CLASS SQLite3::Database::FunctionProxy

### Methods

- ::finalize
- ::new
- ::new
- ::open
- ::quote
- ::step
- #authorizer
- #authorizer=
- #busy_handler
- #busy_timeout
- #busy_timeout=
- #changes
- #close
- #closed?
- #collation
- #commit
- #complete?
- #create_aggregate
- #create_aggregate_handler
- #create_function
- #define_aggregator
- #define_function
- #enable_load_extension
- #encoding
- #errcode
- #errmsg
- #execute
- #execute2
- #execute_batch
- #finalize
- #get_first_row
- #get_first_value
- #instance
- #interrupt
- #last_insert_row_id
- #load_extension
- #prepare
- #query
- #readonly?
- #rollback
- #step
- #total_changes
- #trace
- #transaction
- #transaction_active?
- #translator

### Included Modules

- SQLite3::Pragmas

### Files

- API_CHANGES.rdoc
- Manifest.txt
- README.rdoc

### Class/Module Index

Quicksearch

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- SQLite3::AbortException
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- SQLite3::Constants::ColumnType
- SQLite3::Constants::ErrorCode
- SQLite3::Constants::TextRep
- SQLite3::ConstraintException
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- SQLite3::Database
- SQLite3::Database::FunctionProxy
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- String

No matching classes.

# SQLite3::Database

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.

### Attributes

collations[R]
results_as_hash[RW]

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

### Public Class Methods

finalize( &block ) click to toggle source

    # File lib/sqlite3/database.rb, line 374
    def self.finalize( &block )
      define_method(:finalize, &block)
    end

new(klass) click to toggle source

    # File lib/sqlite3/database.rb, line 453
    def initialize klass
      @klass = klass
      @fp    = FunctionProxy.new
    end

SQLite3::Database.new(file, options = {}) click to toggle source

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=).

    static VALUE initialize(int argc, VALUE *argv, VALUE self)
    {
      sqlite3RubyPtr ctx;
      VALUE file;
      VALUE opts;
      VALUE zvfs;
    #ifdef HAVE_SQLITE3_OPEN_V2
      int mode = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE;
    #endif
      int status;

      Data_Get_Struct(self, sqlite3Ruby, ctx);

      rb_scan_args(argc, argv, "12", &file, &opts, &zvfs);
    #if defined StringValueCStr
      StringValuePtr(file);
      rb_check_safe_obj(file);
    #else
      Check_SafeStr(file);
    #endif
      if(NIL_P(opts)) opts = rb_hash_new();
      else Check_Type(opts, T_HASH);

    #ifdef HAVE_RUBY_ENCODING_H
      if(UTF16_LE_P(file) || UTF16_BE_P(file)) {
        status = sqlite3_open16(utf16_string_value_ptr(file), &ctx->db);
      } else {
    #endif

        if(Qtrue == rb_hash_aref(opts, sym_utf16)) {
          status = sqlite3_open16(utf16_string_value_ptr(file), &ctx->db);
        } else {

    #ifdef HAVE_RUBY_ENCODING_H
          if(!UTF8_P(file)) {
            file = rb_str_export_to_enc(file, rb_utf8_encoding());
          }
    #endif

          if (Qtrue == rb_hash_aref(opts, ID2SYM(rb_intern("readonly")))) {
    #ifdef HAVE_SQLITE3_OPEN_V2
            mode = SQLITE_OPEN_READONLY;
    #else
            rb_raise(rb_eNotImpError, "sqlite3-ruby was compiled against a version of sqlite that does not support readonly databases");
    #endif
          }
    #ifdef HAVE_SQLITE3_OPEN_V2
          status = sqlite3_open_v2(
              StringValuePtr(file),
              &ctx->db,
              mode,
              NIL_P(zvfs) ? NULL : StringValuePtr(zvfs)
          );
    #else
          status = sqlite3_open(
              StringValuePtr(file),
              &ctx->db
          );
    #endif
        }

    #ifdef HAVE_RUBY_ENCODING_H
      }
    #endif

      CHECK(ctx->db, status)

      rb_iv_set(self, "@tracefunc", Qnil);
      rb_iv_set(self, "@authorizer", Qnil);
      rb_iv_set(self, "@encoding", Qnil);
      rb_iv_set(self, "@busy_handler", Qnil);
      rb_iv_set(self, "@collations", rb_hash_new());
      rb_iv_set(self, "@functions", rb_hash_new());
      rb_iv_set(self, "@results_as_hash", rb_hash_aref(opts, sym_results_as_hash));
      rb_iv_set(self, "@type_translation", rb_hash_aref(opts, sym_type_translation));
    #ifdef HAVE_SQLITE3_OPEN_V2
      rb_iv_set(self, "@readonly", mode == SQLITE_OPEN_READONLY ? Qtrue : Qfalse);
    #else
      rb_iv_set(self, "@readonly", Qfalse);
    #endif

      if(rb_block_given_p()) {
        rb_yield(self);
        rb_funcall(self, rb_intern("close"), 0);
      }

      return self;
    }

Also aliased as: open
open(p1, p2 = v2, p3 = v3) click to toggle source
Alias for: new
quote( string ) click to toggle source

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.

    # File lib/sqlite3/database.rb, line 47
    def quote( string )
      string.gsub( /'/, "''" )
    end

step( &block ) click to toggle source

    # File lib/sqlite3/database.rb, line 370
    def self.step( &block )
      define_method(:step, &block)
    end

### Public Instance Methods

authorizer( &block ) click to toggle source

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.

    # File lib/sqlite3/database.rb, line 81
    def authorizer( &block )
      self.authorizer = block
    end

set_authorizer = auth click to toggle source

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.

    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| ... } click to toggle source
busy_handler(Class.new { def call count; end }.new)

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.

    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(p1) click to toggle source
Alias for: busy_timeout=
busy_timeout = ms click to toggle source

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.

    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;
    }

Also aliased as: busy_timeout
changes click to toggle source

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.

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

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

close click to toggle source

Closes this database.

    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;

      return self;
    }

closed? click to toggle source

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

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

      if(!ctx->db) return Qtrue;

      return Qfalse;
    }

collation(name, comparator) click to toggle source

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.

    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() click to toggle source

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`.

    # File lib/sqlite3/database.rb, line 516
    def commit
      execute "commit transaction"
      true
    end

complete?(sql) click to toggle source

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

    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 ) click to toggle source

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.

    # File lib/sqlite3/database.rb, line 366
    def create_aggregate( name, arity, step=nil, finalize=nil,
      text_rep=Constants::TextRep::ANY, &block )

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

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

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

      proxy = factory.new
      proxy.extend(Module.new {
        attr_accessor :ctx

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

        def finalize
          super(@ctx)
        end
      })
      proxy.ctx = FunctionProxy.new
      define_aggregator(name, proxy)
    end

create_aggregate_handler( handler ) click to toggle source

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" )

    # File lib/sqlite3/database.rb, line 451
    def create_aggregate_handler( handler )
      proxy = Class.new do
        def initialize klass
          @klass = klass
          @fp    = FunctionProxy.new
        end

        def step( *args )
          instance.step(@fp, *args)
        end

        def finalize
          instance.finalize @fp
          @instance = nil
          @fp.result
        end

        private

        def instance
          @instance ||= @klass.new
        end
      end
      define_aggregator(handler.name, proxy.new(handler))
      self
    end

create_function(name, arity, text_rep=Constants::TextRep::ANY, &block) click to toggle source

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" )

    # File lib/sqlite3/database.rb, line 321
    def create_function name, arity, text_rep=Constants::TextRep::ANY, &block
      define_function(name) do |*args|
        fp = FunctionProxy.new
        block.call(fp, *args)
        fp.result
      end
      self
    end

define_aggregator(name, aggregator) click to toggle source

Define an aggregate function named `name` using the 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.

    static VALUE define_aggregator(VALUE self, VALUE name, VALUE aggregator)
    {
      sqlite3RubyPtr ctx;
      int arity, status;

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

      arity = sqlite3_obj_method_arity(aggregator, rb_intern("step"));

      status = sqlite3_create_function(
        ctx->db,
        StringValuePtr(name),
        arity,
        SQLITE_UTF8,
        (void *)aggregator,
        NULL,
        rb_sqlite3_step,
        rb_sqlite3_final
      );

      rb_iv_set(self, "@agregator", aggregator);

      CHECK(ctx->db, status);

      return self;
    }

define_function(name) { |args,...| } click to toggle source

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

    static VALUE define_function(VALUE self, VALUE name)
    {
      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),
        SQLITE_UTF8,
        (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) click to toggle source

Enable or disable extension loading.

    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 click to toggle source

Fetch the encoding set on this database

    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 click to toggle source

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

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

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

errmsg click to toggle source

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

    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) click to toggle source

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.

    # File lib/sqlite3/database.rb, line 115
    def execute sql, bind_vars = [], *args, &block
      # FIXME: This is a terrible hack and should be removed but is required
      # for older versions of rails
      hack = Object.const_defined?(:ActiveRecord) && sql =~ /^PRAGMA index_list/

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

        warn(#{caller[0]} is calling SQLite3::Database#execute with nil or multiple bind paramswithout 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.) if $VERBOSE
      end

      prepare( sql ) do |stmt|
        stmt.bind_params(bind_vars)
        columns = stmt.columns
        stmt    = ResultSet.new(self, stmt).to_a if type_translation

        if block_given?
          stmt.each do |row|
            if @results_as_hash
              yield type_translation ? row : ordered_map_for(columns, row)
            else
              yield row
            end
          end
        else
          if @results_as_hash
            stmt.map { |row|
              h = type_translation ? row : ordered_map_for(columns, row)

              # FIXME UGH TERRIBLE HACK!
              h['unique'] = h['unique'].to_s if hack

              h
            }
          else
            stmt.to_a
          end
        end
      end
    end

execute2( sql, *bind_vars ) click to toggle source

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.

    # File lib/sqlite3/database.rb, line 174
    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 ) click to toggle source

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.

    # File lib/sqlite3/database.rb, line 195
    def execute_batch( sql, bind_vars = [], *args )
      # FIXME: remove this stuff later
      unless [Array, Hash].include?(bind_vars.class)
        bind_vars = [bind_vars]
        warn(#{caller[0]} is calling SQLite3::Database#execute_batch with bind parametersthat are not a list of a hash.  Please switch to passing bind parameters as anarray or hash. Support for this behavior will be removed in version 2.0.0.) if $VERBOSE
      end

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

        warn(#{caller[0]} is calling SQLite3::Database#execute_batch with nil or multiple bind paramswithout using an array.  Please switch to passing bind parameters as an array.Support for this behavior will be removed in version 2.0.0.) if $VERBOSE
      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

finalize() click to toggle source

    # File lib/sqlite3/database.rb, line 396
    def finalize
      super(@ctx)
    end

get_first_row( sql, *bind_vars ) click to toggle source

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.

    # File lib/sqlite3/database.rb, line 282
    def get_first_row( sql, *bind_vars )
      execute( sql, *bind_vars ).first
    end

get_first_value( sql, *bind_vars ) click to toggle source

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.

    # File lib/sqlite3/database.rb, line 291
    def get_first_value( sql, *bind_vars )
      execute( sql, *bind_vars ) { |row| return row[0] }
      nil
    end

instance() click to toggle source

    # File lib/sqlite3/database.rb, line 470
    def instance
      @instance ||= @klass.new
    end

interrupt click to toggle source

Interrupts the currently executing operation, causing it to abort.

    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 click to toggle source

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

    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) click to toggle source

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.

    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, RSTRING_PTR(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) click to toggle source

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.

    # File lib/sqlite3/database.rb, line 90
    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 ) click to toggle source

This is a convenience method for creating a statement, binding paramters 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.

    # File lib/sqlite3/database.rb, line 250
    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(#{caller[0]} is calling SQLite3::Database#query with nil or multiple bind paramswithout using an array.  Please switch to passing bind parameters as an array.Support for this will be removed in version 2.0.0.) if $VERBOSE
      end

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

readonly?() click to toggle source

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

    # File lib/sqlite3/database.rb, line 532
    def readonly?
      @readonly
    end

rollback() click to toggle source

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`.

    # File lib/sqlite3/database.rb, line 525
    def rollback
      execute "rollback transaction"
      true
    end

step( *args ) click to toggle source

    # File lib/sqlite3/database.rb, line 392
    def step( *args )
      super(@ctx, *args)
    end

total_changes click to toggle source

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

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

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

trace { |sql| ... } click to toggle source
trace(Class.new { def call sql; end }.new)

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.

    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 ) click to toggle source

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.

    # File lib/sqlite3/database.rb, line 494
    def transaction( mode = :deferred )
      execute "begin #{mode.to_s} transaction"

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

      true
    end

transaction_active? click to toggle source

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

    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;
    }

translator() click to toggle source

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.)

    # File lib/sqlite3/database.rb, line 73
    def translator
      @translator ||= Translator.new
    end

[Validate]

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