class SQLite3::Statement
A statement represents a prepared-but-unexecuted SQL query. It will rarely (if ever) be instantiated directly by a client, and is most often obtained via the SQLite3::Database#prepare method.
Attributes
This is any text that followed the first valid SQL statement in the text with which the statement was initialized. If there was no trailing text, this will be the empty string.
Public Class Methods
Create a new statement attached to the given Database instance, and which encapsulates the given SQL text. If the text contains more than one statement (i.e., separated by semicolons), then the remainder property will be set to the trailing text.
static VALUE initialize(VALUE self, VALUE db, VALUE sql) { sqlite3RubyPtr db_ctx; sqlite3StmtRubyPtr ctx; const char *tail = NULL; int status; StringValue(sql); Data_Get_Struct(db, sqlite3Ruby, db_ctx); Data_Get_Struct(self, sqlite3StmtRuby, ctx); if(!db_ctx->db) rb_raise(rb_eArgError, "prepare called on a closed database"); if(!UTF8_P(sql)) { sql = rb_str_export_to_enc(sql, rb_utf8_encoding()); } #ifdef HAVE_SQLITE3_PREPARE_V2 status = sqlite3_prepare_v2( #else status = sqlite3_prepare( #endif db_ctx->db, (const char *)StringValuePtr(sql), (int)RSTRING_LEN(sql), &ctx->st, &tail ); CHECK(db_ctx->db, status); rb_iv_set(self, "@connection", db); rb_iv_set(self, "@remainder", rb_str_new2(tail)); rb_iv_set(self, "@columns", Qnil); rb_iv_set(self, "@types", Qnil); return self; }
Public Instance Methods
Returns true if the statement is currently active, meaning it has an open result set.
# File lib/sqlite3/statement.rb, line 94 def active? !done? end
Binds value to the named (or positional) placeholder. If param
is a Fixnum, it is treated as an index for a positional placeholder.
Otherwise it is used as the name of the placeholder to bind to.
See also bind_params.
static VALUE bind_param(VALUE self, VALUE key, VALUE value) { sqlite3StmtRubyPtr ctx; int status; int index; Data_Get_Struct(self, sqlite3StmtRuby, ctx); REQUIRE_OPEN_STMT(ctx); switch(TYPE(key)) { case T_SYMBOL: key = rb_funcall(key, rb_intern("to_s"), 0); case T_STRING: if(RSTRING_PTR(key)[0] != ':') key = rb_str_plus(rb_str_new2(":"), key); index = sqlite3_bind_parameter_index(ctx->st, StringValuePtr(key)); break; default: index = (int)NUM2INT(key); } if(index == 0) rb_raise(rb_path2class("SQLite3::Exception"), "no such bind parameter"); switch(TYPE(value)) { case T_STRING: if(CLASS_OF(value) == cSqlite3Blob || rb_enc_get_index(value) == rb_ascii8bit_encindex() ) { status = sqlite3_bind_blob( ctx->st, index, (const char *)StringValuePtr(value), (int)RSTRING_LEN(value), SQLITE_TRANSIENT ); } else { if (UTF16_LE_P(value) || UTF16_BE_P(value)) { status = sqlite3_bind_text16( ctx->st, index, (const char *)StringValuePtr(value), (int)RSTRING_LEN(value), SQLITE_TRANSIENT ); } else { if (!UTF8_P(value) || !USASCII_P(value)) { value = rb_str_encode(value, rb_enc_from_encoding(rb_utf8_encoding()), 0, Qnil); } status = sqlite3_bind_text( ctx->st, index, (const char *)StringValuePtr(value), (int)RSTRING_LEN(value), SQLITE_TRANSIENT ); } } break; case T_BIGNUM: { sqlite3_int64 num64; if (bignum_to_int64(value, &num64)) { status = sqlite3_bind_int64(ctx->st, index, num64); break; } } case T_FLOAT: status = sqlite3_bind_double(ctx->st, index, NUM2DBL(value)); break; case T_FIXNUM: status = sqlite3_bind_int64(ctx->st, index, (sqlite3_int64)FIX2LONG(value)); break; case T_NIL: status = sqlite3_bind_null(ctx->st, index); break; default: rb_raise(rb_eRuntimeError, "can't prepare %s", rb_class2name(CLASS_OF(value))); break; } CHECK(sqlite3_db_handle(ctx->st), status); return self; }
Return the number of bind parameters
static VALUE bind_parameter_count(VALUE self) { sqlite3StmtRubyPtr ctx; Data_Get_Struct(self, sqlite3StmtRuby, ctx); REQUIRE_OPEN_STMT(ctx); return INT2NUM((long)sqlite3_bind_parameter_count(ctx->st)); }
Binds the given variables to the corresponding placeholders in the SQL text.
See SQLite3::Database#execute for a description of the valid placeholder syntaxes.
Example:
stmt = db.prepare( "select * from table where a=? and b=?" ) stmt.bind_params( 15, "hello" )
See also execute, bind_param, #bind_param, and #bind_params.
# File lib/sqlite3/statement.rb, line 35 def bind_params( *bind_vars ) index = 1 bind_vars.flatten.each do |var| if Hash === var var.each { |key, val| bind_param key, val } else bind_param index, var index += 1 end end end
Resets the statement. This is typically done internally, though it might occassionally be necessary to manually reset the statement.
static VALUE clear_bindings_bang(VALUE self) { sqlite3StmtRubyPtr ctx; Data_Get_Struct(self, sqlite3StmtRuby, ctx); REQUIRE_OPEN_STMT(ctx); sqlite3_clear_bindings(ctx->st); ctx->done_p = 0; return self; }
Closes the statement by finalizing the underlying statement handle. The statement must not be used after being closed.
static VALUE sqlite3_rb_close(VALUE self) { sqlite3StmtRubyPtr ctx; Data_Get_Struct(self, sqlite3StmtRuby, ctx); REQUIRE_OPEN_STMT(ctx); sqlite3_finalize(ctx->st); ctx->st = NULL; return self; }
Returns true if the statement has been closed.
static VALUE closed_p(VALUE self) { sqlite3StmtRubyPtr ctx; Data_Get_Struct(self, sqlite3StmtRuby, ctx); if(!ctx->st) return Qtrue; return Qfalse; }
Returns the number of columns to be returned for this statement
static VALUE column_count(VALUE self) { sqlite3StmtRubyPtr ctx; Data_Get_Struct(self, sqlite3StmtRuby, ctx); REQUIRE_OPEN_STMT(ctx); return INT2NUM((long)sqlite3_column_count(ctx->st)); }
Get the column type at index
. 0 based.
static VALUE column_decltype(VALUE self, VALUE index) { sqlite3StmtRubyPtr ctx; const char * name; Data_Get_Struct(self, sqlite3StmtRuby, ctx); REQUIRE_OPEN_STMT(ctx); name = sqlite3_column_decltype(ctx->st, (int)NUM2INT(index)); if(name) return rb_str_new2(name); return Qnil; }
Get the column name at index
. 0 based.
static VALUE column_name(VALUE self, VALUE index) { sqlite3StmtRubyPtr ctx; const char * name; Data_Get_Struct(self, sqlite3StmtRuby, ctx); REQUIRE_OPEN_STMT(ctx); name = sqlite3_column_name(ctx->st, (int)NUM2INT(index)); if(name) return SQLITE3_UTF8_STR_NEW2(name); return Qnil; }
Return an array of the column names for this statement. Note that this may execute the statement in order to obtain the metadata; this makes it a (potentially) expensive operation.
# File lib/sqlite3/statement.rb, line 101 def columns get_metadata unless @columns return @columns end
Return the database name for the column at column_index
static VALUE database_name(VALUE self, VALUE index) { sqlite3StmtRubyPtr ctx; Data_Get_Struct(self, sqlite3StmtRuby, ctx); REQUIRE_OPEN_STMT(ctx); return SQLITE3_UTF8_STR_NEW2( sqlite3_column_database_name(ctx->st, NUM2INT(index))); }
returns true if all rows have been returned.
static VALUE done_p(VALUE self) { sqlite3StmtRubyPtr ctx; Data_Get_Struct(self, sqlite3StmtRuby, ctx); if(ctx->done_p) return Qtrue; return Qfalse; }
# File lib/sqlite3/statement.rb, line 106 def each loop do val = step break self if done? yield val end end
Execute the statement. This creates a new ResultSet object for the statement's virtual machine. If a block was given, the new ResultSet will be yielded to it; otherwise, the ResultSet will be returned.
Any parameters will be bound to the statement using bind_params.
Example:
stmt = db.prepare( "select * from table" ) stmt.execute do |result| ... end
See also bind_params, execute!.
# File lib/sqlite3/statement.rb, line 61 def execute( *bind_vars ) reset! if active? || done? bind_params(*bind_vars) unless bind_vars.empty? @results = ResultSet.new(@connection, self) step if 0 == column_count yield @results if block_given? @results end
Execute the statement. If no block was given, this returns an array of rows returned by executing the statement. Otherwise, each row will be yielded to the block.
Any parameters will be bound to the statement using bind_params.
Example:
stmt = db.prepare( "select * from table" ) stmt.execute! do |row| ... end
See also bind_params, execute.
# File lib/sqlite3/statement.rb, line 87 def execute!( *bind_vars, &block ) execute(*bind_vars) block_given? ? each(&block) : to_a end
Resets the statement. This is typically done internally, though it might occassionally be necessary to manually reset the statement.
static VALUE reset_bang(VALUE self) { sqlite3StmtRubyPtr ctx; Data_Get_Struct(self, sqlite3StmtRuby, ctx); REQUIRE_OPEN_STMT(ctx); sqlite3_reset(ctx->st); ctx->done_p = 0; return self; }
static VALUE step(VALUE self) { sqlite3StmtRubyPtr ctx; sqlite3_stmt *stmt; int value, length; VALUE list; rb_encoding * internal_encoding; Data_Get_Struct(self, sqlite3StmtRuby, ctx); REQUIRE_OPEN_STMT(ctx); if(ctx->done_p) return Qnil; { VALUE db = rb_iv_get(self, "@connection"); rb_funcall(db, rb_intern("encoding"), 0); internal_encoding = rb_default_internal_encoding(); } stmt = ctx->st; value = sqlite3_step(stmt); if (rb_errinfo() != Qnil) { /* some user defined function was invoked as a callback during step and * it raised an exception that has been suppressed until step returns. * Now re-raise it. */ VALUE exception = rb_errinfo(); rb_set_errinfo(Qnil); rb_exc_raise(exception); } length = sqlite3_column_count(stmt); list = rb_ary_new2((long)length); switch(value) { case SQLITE_ROW: { int i; for(i = 0; i < length; i++) { switch(sqlite3_column_type(stmt, i)) { case SQLITE_INTEGER: rb_ary_push(list, LL2NUM(sqlite3_column_int64(stmt, i))); break; case SQLITE_FLOAT: rb_ary_push(list, rb_float_new(sqlite3_column_double(stmt, i))); break; case SQLITE_TEXT: { VALUE str = rb_str_new( (const char *)sqlite3_column_text(stmt, i), (long)sqlite3_column_bytes(stmt, i) ); rb_enc_associate_index(str, rb_utf8_encindex()); if(internal_encoding) str = rb_str_export_to_enc(str, internal_encoding); rb_ary_push(list, str); } break; case SQLITE_BLOB: { VALUE str = rb_str_new( (const char *)sqlite3_column_blob(stmt, i), (long)sqlite3_column_bytes(stmt, i) ); rb_ary_push(list, str); } break; case SQLITE_NULL: rb_ary_push(list, Qnil); break; default: rb_raise(rb_eRuntimeError, "bad type"); } } } break; case SQLITE_DONE: ctx->done_p = 1; return Qnil; break; default: sqlite3_reset(stmt); ctx->done_p = 0; CHECK(sqlite3_db_handle(ctx->st), value); } return list; }
Return an array of the data types for each column in this statement. Note that this may execute the statement in order to obtain the metadata; this makes it a (potentially) expensive operation.
# File lib/sqlite3/statement.rb, line 117 def types must_be_open! get_metadata unless @types @types end
Private Instance Methods
A convenience method for obtaining the metadata about the query. Note that this will actually execute the SQL, which means it can be a (potentially) expensive operation.
# File lib/sqlite3/statement.rb, line 135 def get_metadata @columns = Array.new(column_count) do |column| column_name column end @types = Array.new(column_count) do |column| column_decltype column end end