package types import ( "fmt" "strings" ) type colType int const ( integer colType = iota boolean bigint numeric bytea varchar text ) type column struct { name string typ colType } type Table struct { Name string Columns []column conflictClause string } func (tbl *Table) ToCsvRow(args ...interface{}) []string { var row []string for i, col := range tbl.Columns { row = append(row, col.typ.formatter()(args[i])) } return row } func (tbl *Table) ToInsertStatement() string { var colnames, placeholders []string for i, col := range tbl.Columns { colnames = append(colnames, col.name) placeholders = append(placeholders, fmt.Sprintf("$%d", i+1)) } return fmt.Sprintf( "INSERT INTO %s (%s) VALUES (%s) %s", tbl.Name, strings.Join(colnames, ", "), strings.Join(placeholders, ", "), tbl.conflictClause, ) } type colfmt = func(interface{}) string func sprintf(f string) colfmt { return func(x interface{}) string { return fmt.Sprintf(f, x) } } func (typ colType) formatter() colfmt { switch typ { case integer: return sprintf("%d") case boolean: return func(x interface{}) string { if x.(bool) { return "t" } return "f" } case bigint: return sprintf("%s") case numeric: return sprintf("%d") case bytea: return sprintf(`\x%x`) case varchar: return sprintf("%s") case text: return sprintf("%s") } panic("unreachable") }