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 Database#prepare method.

Attributes

remainder[R]

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

SQLite3::Statement.new(db, sql) click to toggle source

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.

# File lib/sqlite3/statement.rb, line 28
def initialize(db, sql)
  raise ArgumentError, "prepare called on a closed database" if db.closed?

  sql = sql.encode(Encoding::UTF_8) if sql && sql.encoding != Encoding::UTF_8

  @connection = db
  @columns = nil
  @types = nil
  @remainder = prepare db, sql
end

Public Instance Methods

active?() click to toggle source

Returns true if the statement is currently active, meaning it has an open result set.

# File lib/sqlite3/statement.rb, line 111
def active?
  !done?
end
bind_param(key, value) click to toggle source

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;

    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(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;
}
bind_parameter_count click to toggle source

Return the number of bind parameters

static VALUE
bind_parameter_count(VALUE self)
{
    sqlite3StmtRubyPtr ctx;
    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    return INT2NUM(sqlite3_bind_parameter_count(ctx->st));
}
bind_params(*bind_vars) click to toggle source

Binds the given variables to the corresponding placeholders in the SQL text.

See 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, Statement#bind_param, and Statement#bind_params.

# File lib/sqlite3/statement.rb, line 52
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
clear_bindings! click to toggle source

Resets the statement. This is typically done internally, though it might occasionally be necessary to manually reset the statement.

static VALUE
clear_bindings_bang(VALUE self)
{
    sqlite3StmtRubyPtr ctx;

    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    sqlite3_clear_bindings(ctx->st);

    ctx->done_p = 0;

    return self;
}
close click to toggle source

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;

    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_OPEN_STMT(ctx);

    sqlite3_finalize(ctx->st);
    ctx->st = NULL;

    return self;
}
closed? click to toggle source

Returns true if the statement has been closed.

static VALUE
closed_p(VALUE self)
{
    sqlite3StmtRubyPtr ctx;
    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    if (!ctx->st) { return Qtrue; }

    return Qfalse;
}
column_count click to toggle source

Returns the number of columns to be returned for this statement

static VALUE
column_count(VALUE self)
{
    sqlite3StmtRubyPtr ctx;
    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    return INT2NUM(sqlite3_column_count(ctx->st));
}
column_decltype(index) click to toggle source

Get the column type at index. 0 based.

static VALUE
column_decltype(VALUE self, VALUE index)
{
    sqlite3StmtRubyPtr ctx;
    const char *name;

    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    name = sqlite3_column_decltype(ctx->st, (int)NUM2INT(index));

    if (name) { return rb_str_new2(name); }
    return Qnil;
}
column_name(index) click to toggle source

Get the column name at index. 0 based.

static VALUE
column_name(VALUE self, VALUE index)
{
    sqlite3StmtRubyPtr ctx;
    const char *name;

    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    name = sqlite3_column_name(ctx->st, (int)NUM2INT(index));

    VALUE ret = Qnil;

    if (name) {
        ret = interned_utf8_cstr(name);
    }
    return ret;
}
columns() click to toggle source

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 118
def columns
  get_metadata unless @columns
  @columns
end
database_name(column_index) click to toggle source

Return the database name for the column at column_index

static VALUE
database_name(VALUE self, VALUE index)
{
    sqlite3StmtRubyPtr ctx;
    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    return SQLITE3_UTF8_STR_NEW2(
               sqlite3_column_database_name(ctx->st, NUM2INT(index)));
}
done? click to toggle source

returns true if all rows have been returned.

static VALUE
done_p(VALUE self)
{
    sqlite3StmtRubyPtr ctx;
    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    if (ctx->done_p) { return Qtrue; }
    return Qfalse;
}
each() { |val| ... } click to toggle source
# File lib/sqlite3/statement.rb, line 123
def each
  loop do
    val = step
    break self if done?
    yield val
  end
end
execute(*bind_vars) { |results| ... } click to toggle source

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 78
def execute(*bind_vars)
  reset! if active? || done?

  bind_params(*bind_vars) unless bind_vars.empty?
  results = @connection.build_result_set self

  step if column_count == 0

  yield results if block_given?
  results
end
execute!(*bind_vars, &block) click to toggle source

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 104
def execute!(*bind_vars, &block)
  execute(*bind_vars)
  block ? each(&block) : to_a
end
expanded_sql click to toggle source

Returns the SQL statement used to create this prepared statement, but with bind parameters substituted in to the statement.

static VALUE
get_expanded_sql(VALUE self)
{
    sqlite3StmtRubyPtr ctx;
    char *expanded_sql;
    VALUE rb_expanded_sql;

    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    expanded_sql = sqlite3_expanded_sql(ctx->st);
    rb_expanded_sql = rb_obj_freeze(SQLITE3_UTF8_STR_NEW2(expanded_sql));
    sqlite3_free(expanded_sql);

    return rb_expanded_sql;
}
memory_used click to toggle source

Return the approximate number of bytes of heap memory used to store the prepared statement

static VALUE
memused(VALUE self)
{
    sqlite3StmtRubyPtr ctx;
    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    return INT2NUM(sqlite3_stmt_status(ctx->st, SQLITE_STMTSTATUS_MEMUSED, 0));
}
reset! click to toggle source

Resets the statement. This is typically done internally, though it might occasionally be necessary to manually reset the statement.

static VALUE
reset_bang(VALUE self)
{
    sqlite3StmtRubyPtr ctx;

    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    sqlite3_reset(ctx->st);

    ctx->done_p = 0;

    return self;
}
sql click to toggle source

Returns the SQL statement used to create this prepared statement

static VALUE
get_sql(VALUE self)
{
    sqlite3StmtRubyPtr ctx;
    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    return rb_obj_freeze(SQLITE3_UTF8_STR_NEW2(sqlite3_sql(ctx->st)));
}
stat(key = nil) click to toggle source

Returns a Hash containing information about the statement. The contents of the hash are implementation specific and may change in the future without notice. The hash includes information about internal statistics about the statement such as:

- +fullscan_steps+: the number of times that SQLite has stepped forward

in a table as part of a full table scan

- +sorts+: the number of sort operations that have occurred
- +autoindexes+: the number of rows inserted into transient indices

that were created automatically in order to help joins run faster

- +vm_steps+: the number of virtual machine operations executed by the

prepared statement

- +reprepares+: the number of times that the prepare statement has been

automatically regenerated due to schema changes or changes to bound parameters that might affect the query plan

- +runs+: the number of times that the prepared statement has been run
- +filter_misses+: the number of times that the Bloom filter returned

a find, and thus the join step had to be processed as normal

- +filter_hits+: the number of times that a join step was bypassed

because a Bloom filter returned not-found

# File lib/sqlite3/statement.rb, line 167
def stat key = nil
  if key
    stat_for(key)
  else
    stats_as_hash
  end
end
step() click to toggle source
static VALUE
step(VALUE self)
{
    sqlite3StmtRubyPtr ctx;
    sqlite3_stmt *stmt;
    int value, length;
    VALUE list;
    rb_encoding *internal_encoding;

    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    if (ctx->done_p) { return Qnil; }

    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++) {
                VALUE val;

                switch (sqlite3_column_type(stmt, i)) {
                    case SQLITE_INTEGER:
                        val = LL2NUM(sqlite3_column_int64(stmt, i));
                        break;
                    case SQLITE_FLOAT:
                        val = rb_float_new(sqlite3_column_double(stmt, i));
                        break;
                    case SQLITE_TEXT: {
                        val = rb_utf8_str_new(
                                  (const char *)sqlite3_column_text(stmt, i),
                                  (long)sqlite3_column_bytes(stmt, i)
                              );
                        if (internal_encoding) {
                            val = rb_str_export_to_enc(val, internal_encoding);
                        }
                        rb_obj_freeze(val);
                    }
                    break;
                    case SQLITE_BLOB: {
                        val = rb_str_new(
                                  (const char *)sqlite3_column_blob(stmt, i),
                                  (long)sqlite3_column_bytes(stmt, i)
                              );
                        rb_obj_freeze(val);
                    }
                    break;
                    case SQLITE_NULL:
                        val = Qnil;
                        break;
                    default:
                        rb_raise(rb_eRuntimeError, "bad type");
                }

                rb_ary_store(list, (long)i, val);
            }
        }
        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);
    }

    rb_obj_freeze(list);

    return list;
}
types() click to toggle source

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 134
def types
  must_be_open!
  get_metadata unless @types
  @types
end

Private Instance Methods

get_metadata() click to toggle source

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 180
def get_metadata
  @columns = Array.new(column_count) do |column|
    column_name column
  end
  @types = Array.new(column_count) do |column|
    val = column_decltype(column)
    val&.downcase
  end
end
prepare(p1, p2) click to toggle source
static VALUE
prepare(VALUE self, VALUE db, VALUE sql)
{
    sqlite3RubyPtr db_ctx = sqlite3_database_unwrap(db);
    sqlite3StmtRubyPtr ctx;
    const char *tail = NULL;
    int status;

    StringValue(sql);

    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    /* Dereferencing a pointer to the database struct will be faster than accessing it through the
     * instance variable @connection. The struct pointer is guaranteed to be live because instance
     * variable will keep it from being GCed. */
    ctx->db = db_ctx;

#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_PREPARE(db_ctx->db, status, StringValuePtr(sql));
    timespecclear(&db_ctx->stmt_deadline);

    return rb_utf8_str_new_cstr(tail);
}
stmt_stat(hash_or_key) click to toggle source

Returns a Hash containing information about the statement.

static VALUE
stat_for(VALUE self, VALUE key)
{
    sqlite3StmtRubyPtr ctx;
    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    if (SYMBOL_P(key)) {
        size_t value = stmt_stat_internal(key, ctx->st);
        return SIZET2NUM(value);
    } else {
        rb_raise(rb_eTypeError, "non-symbol given");
    }
}
stats_as_hash(hash) click to toggle source

Returns a Hash containing information about the statement.

static VALUE
stats_as_hash(VALUE self)
{
    sqlite3StmtRubyPtr ctx;
    TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);

    REQUIRE_LIVE_DB(ctx);
    REQUIRE_OPEN_STMT(ctx);

    VALUE arg = rb_hash_new();

    stmt_stat_internal(arg, ctx->st);
    return arg;
}