Class: DuckDB::Connection

Inherits:
Object
  • Object
show all
Defined in:
lib/duckdb/connection.rb,
ext/duckdb/connection.c

Overview

The DuckDB::Connection encapsulates connection with DuckDB database.

require 'duckdb'
db = DuckDB::Database.open
con = db.connect
con.query(sql)

Instance Method Summary collapse

Instance Method Details

#appender(table) {|appender| ... } ⇒ Object

returns Appender object. The first argument is table name

Yields:



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# File 'lib/duckdb/connection.rb', line 109

def appender(table)
  appender = create_appender(table)

  return appender unless block_given?

  yield appender
  appender.flush
  appender.close
end

#async_query(sql, *args, **kwargs) ⇒ Object Also known as: async_execute

executes sql with args asynchronously. The first argument sql must be SQL string. The rest arguments are parameters of SQL string. This method returns DuckDB::PendingResult object.

require 'duckdb'
db = DuckDB::Database.open('duckdb_file')
con = db.connect

sql = 'SELECT * FROM users WHERE name = $name AND email = $email'
pending_result = con.async_query(sql, name: 'Dave', email: '[email protected]')
pending_result.execute_task while pending_result.state == :not_ready
result = pending_result.execute_pending
result.each.first



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# File 'lib/duckdb/connection.rb', line 52

def async_query(sql, *args, **kwargs)
  stmt = PreparedStatement.new(self, sql)
  stmt.bind_args(*args, **kwargs)
  stmt.pending_prepared
end

#async_query_stream(sql, *args, **kwargs) ⇒ Object

executes sql with args asynchronously and provides streaming result. The first argument sql must be SQL string. The rest arguments are parameters of SQL string. This method returns DuckDB::PendingResult object.

require 'duckdb'
DuckDB::Result.use_chunk_each = true # must be true
db = DuckDB::Database.open('duckdb_file')
con = db.connect

sql = 'SELECT * FROM users WHERE name = $name AND email = $email'
pending_result = con.async_query_stream(sql, name: 'Dave', email: '[email protected]')

pending_result.execute_task while pending_result.state == :not_ready
result = pending_result.execute_pending
result.each.first



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# File 'lib/duckdb/connection.rb', line 76

def async_query_stream(sql, *args, **kwargs)
  stmt = PreparedStatement.new(self, sql)
  stmt.bind_args(*args, **kwargs)
  stmt.pending_prepared_stream
end

#connect(db) ⇒ Object Also known as: open

connects DuckDB database The first argument is DuckDB::Database object



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# File 'lib/duckdb/connection.rb', line 86

def connect(db)
  conn = _connect(db)
  return conn unless block_given?

  begin
    yield conn
  ensure
    conn.disconnect
  end
end

#disconnect ⇒ Object Also known as: close 



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# File 'ext/duckdb/connection.c', line 59

static VALUE duckdb_connection_disconnect(VALUE self) {
    rubyDuckDBConnection *ctx;

    TypedData_Get_Struct(self, rubyDuckDBConnection, &connection_data_type, ctx);
    duckdb_disconnect(&(ctx->con));

    return self;
}

#interrupt ⇒ nil

Interrupts the currently running query.

db = DuckDB::Database.open
conn = db.connect
con.query('SET ENABLE_PROGRESS_BAR=true')
con.query('SET ENABLE_PROGRESS_BAR_PRINT=false')
pending_result = con.async_query('slow query')

pending_result.execute_task
con.interrupt # => nil

Returns:

  • (nil) 


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# File 'ext/duckdb/connection.c', line 83

static VALUE duckdb_connection_interrupt(VALUE self) {
    rubyDuckDBConnection *ctx;

    TypedData_Get_Struct(self, rubyDuckDBConnection, &connection_data_type, ctx);
    duckdb_interrupt(ctx->con);

    return Qnil;
}

#prepared_statement(str) ⇒ Object

returns PreparedStatement object. The first argument is SQL string.



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# File 'lib/duckdb/connection.rb', line 101

def prepared_statement(str)
  PreparedStatement.new(self, str)
end

#query(sql, *args, **kwargs) ⇒ Object Also known as: execute

executes sql with args. The first argument sql must be SQL string. The rest arguments are parameters of SQL string.

require 'duckdb'
db = DuckDB::Database.open('duckdb_file')
con = db.connect
users = con.query('SELECT * FROM users')
sql = 'SELECT * FROM users WHERE name = ? AND email = ?'
dave = con.query(sql, 'Dave', '[email protected]')

# or You can use named parameter.

sql = 'SELECT * FROM users WHERE name = $name AND email = $email'
dave = con.query(sql, name: 'Dave', email: '[email protected]')



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# File 'lib/duckdb/connection.rb', line 28

def query(sql, *args, **kwargs)
  return query_sql(sql) if args.empty? && kwargs.empty?

  stmt = PreparedStatement.new(self, sql)
  stmt.bind_args(*args, **kwargs)
  stmt.execute
end

#query_progress ⇒ Object

Returns the progress of the currently running query.

require 'duckdb'

db = DuckDB::Database.open
conn = db.connect
con.query('SET ENABLE_PROGRESS_BAR=true')
con.query('SET ENABLE_PROGRESS_BAR_PRINT=false')
con.query_progress # => -1.0
pending_result = con.async_query('slow query')
con.query_progress # => 0.0
pending_result.execute_task
con.query_progress # => Float



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# File 'ext/duckdb/connection.c', line 107

static VALUE duckdb_connection_query_progress(VALUE self) {
    rubyDuckDBConnection *ctx;
#ifdef HAVE_DUCKDB_H_GE_V0_10_0
    duckdb_query_progress_type progress;
#else
    double progress;
#endif

    TypedData_Get_Struct(self, rubyDuckDBConnection, &connection_data_type, ctx);
    progress = duckdb_query_progress(ctx->con);

#ifdef HAVE_DUCKDB_H_GE_V0_10_0
    return rb_funcall(mDuckDBConverter, rb_intern("_to_query_progress"), 3, DBL2NUM(progress.percentage), ULL2NUM(progress.rows_processed), ULL2NUM(progress.total_rows_to_process));
#else
    return DBL2NUM(progress);
#endif
}