// Compile outputs the INSERT statement using the given dialect and parameters.
// An error may be returned because of a pre-existing error or because
// an error occurred during compilation.
func (stmt InsertStmt) Compile(d dialect.Dialect, ps *Parameters) (string, error) {
// Check for delayed errors
if err := stmt.Error(); err != nil {
return "", err
}
cols := len(stmt.columns)
// No columns? no statement!
if cols == 0 {
return "", ErrNoColumns
}
columns := make([]string, len(stmt.columns))
for i, column := range stmt.columns {
columns[i] = fmt.Sprintf(`"%s"`, column.Name())
}
// args must be divisable by cols without remainder
if len(stmt.args)%cols != 0 {
return "", fmt.Errorf(
`sol: size mismatch between arguments and columns during INSERT: %d is not a multiple of %d`,
len(stmt.args),
cols,
)
}
// Determine the number of rows that will be inserted
rows := len(stmt.args) / cols
// If there are no arguments, default to one rows and create
// placeholder values
if rows == 0 {
rows = 1
stmt.args = make([]interface{}, cols)
for i, _ := range stmt.args {
stmt.args[i] = nil
}
}
parameters := make([]string, rows)
var param int
for i := 0; i < rows; i += 1 {
row := make([]string, cols)
for j := 0; j < cols; j += 1 {
// Parameters are dialect specific
row[j] = d.Param(param)
ps.Add(stmt.args[param])
param += 1
}
// TODO Parameters compilation?
parameters[i] = fmt.Sprintf(`(%s)`, strings.Join(row, ", "))
}
// TODO Bulk insert syntax is dialect specific
return fmt.Sprintf(
`INSERT INTO %s (%s) VALUES %s`,
stmt.table.Name(),
strings.Join(columns, ", "),
strings.Join(parameters, ", "),
), nil
}
// Parameter compilation is dialect dependent. For instance, dialects such
// as PostGres require the parameter index.
func (p *Parameter) Compile(d dialect.Dialect, ps *Parameters) (string, error) {
ps.Add(p.Value)
return d.Param(ps.Len() - 1), nil
}