migrate/query.go

package migrate

import "database/sql"

func createSchemaIfNotExists(tx *sql.Tx, schema string) error {
	row := tx.QueryRow(`SELECT 1 FROM information_schema.schemata WHERE schema_name = '` + schema + `'`)
	err := row.Scan(new(int))
	if err == sql.ErrNoRows {
		_, err = tx.Exec(`CREATE SCHEMA ` + schema)
		if err != nil {
			return err
		}
	}
	return err
}

func createTableIfNotExists(tx *sql.Tx, schema, table string) (string, error) {
	versionTable := table
	var schemaCond string

	if schema != `` {
		versionTable = schema + `.` + table
		schemaCond = ` AND table_schema = '` + schema + `'`
	}

	row := tx.QueryRow(`SELECT 1 FROM information_schema.tables WHERE table_name = '` + table + `'` + schemaCond)
	err := row.Scan(new(int))
	if err == sql.ErrNoRows {
		_, err = tx.Exec(`CREATE TABLE ` + versionTable + ` (version integer NOT NULL PRIMARY KEY)`)
		if err != nil {
			return ``, err
		}
	}
	return versionTable, err
}