问题
I want to delete multiple database entries at once. Each entry should only be deleted if 3 fields match (here: name, email, age).
If I'd just wanted to delete by a single property, I'd go for:
String sql = "DELETE FROM persons WHERE (email) IN (?)";
JdbcTemplate template;
template.execute(sql, Arrays.asList(emails...));
But what if my condition is formed by multiple fields?
String sql = "DELETE FROM persons WHERE (name, email, age) IN (?, ?, ?)";
JdbcTemplate template;
template.execute(sql, ...); ???
The condition should always match all 3 fields (AND)!
回答1:
Use the batchUpdate(sql, batchArgs, argTypes) method.
String sql = "DELETE FROM persons WHERE name = ? AND email = ? AND age = ?";
int[] argTypes = { Types.VARCHAR, Types.VARCHAR, Types.INTEGER };
List<Object[]> batchArgs = new ArrayList<>();
batchArgs.add(new Object[] { "John Doe", "john@example.com", 42 });
batchArgs.add(new Object[] { "Jane Smith", "jane@example.com", 47 });
. . .
JdbcTemplate template = ...;
int[] rowCounts = template.batchUpdate(sql, batchArgs, argTypes);
回答2:
A batchUpdate is what you are looking for here. You would need to change/tweak your query a little bit though.
If you can pass a list of objects (you must match the class members with the values on the SQL query), it can be done automatically:
private final NamedParameterJdbcTemplate namedParameterJdbcTemplate;
// class People { String name; String email; Integer age; }
final String sql = "DELETE FROM persons WHERE name = :name AND email = :email AND age = :age";
final SqlParameterSource[] batchArgs = SqlParameterSourceUtils.createBatch(people.toArray()); // List<People>
final int[] results = namedParameterJdbcTemplate.batchUpdate(sql, batchArgs);
logger.debug("{} record(s) inserted successfully", results.length);
The other approach would be what @Andreas proposed.
I would also recommend to use, always, parameterized queries: DELETE FROM persons WHERE name = :name AND email = :email AND age = :age.
来源：https://stackoverflow.com/questions/50471046/how-to-execute-multi-batch-delete-in-jdbctemplate