Insert

Hint

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You can insert data using an entity bean or a Map as the container.

Use a bean as the data container

User user = new User();
user.setId(20);
user.setName("new name");
user.setAge(88);
user.setCreateTime(new Date());

LambdaTemplate lambda = ...;
int result = lambda.insert(User.class)
                   .applyEntity(user)
                   .executeSumResult();
// result is 1

Use a Map as the data container

Map<String, Object> user = new HashMap<>();
user.put("id", 20);
user.put("name", "new name");
user.put("age", 88);
user.put("create_time", new Date());

LambdaTemplate lambda = ...;
int result = lambda.insert(User.class)
                   .applyMap(user)
                   .executeSumResult();
// result is 1

Batching

Use batch insert when inserting many records.

User user1 = new User();
...
User user2 = new User();
...
User user3 = new User();
...

LambdaTemplate lambda = ...
int result = lambda.insert(User.class)
                   .applyEntity(user1, user2, user3);               // 不定参方式
                 //.applyEntity(new User[]{user1, user2, user3});  // 使用数组
                 //.applyEntity(Arrays.asList(user1, user2, user3));// 使用 List
                   .executeSumResult();
// result is 3

• For Map data, use applyMap instead of applyEntity.
• You can call applyEntity/applyMap multiple times before executeSumResult to stage batches.

Write conflicts

Unintentionally inserting duplicates can cause primary-key conflicts. A common approach is “check then update/insert,” e.g.:

常规方法

if (adapter.queryByEntity(User.class)
            .eq(User::getId,user.getId())
            .queryForCount() > 0) {
  // update
} else {
  // insert
}

Databases often provide more efficient conflict handling, for example:

• MySQL: ON DUPLICATE KEY UPDATE on INSERT.
• Oracle: MERGE INTO ... WHEN MATCHED THEN ... WHEN NOT MATCHED THEN ....

Using these dialect features requires:

• dbVisitor dialect support; see dialect support.
• Setting a conflict strategy via onDuplicateStrategy.

dbVisitor provides three conflict strategies to avoid extra code:

• Into: plain INSERT INTO (throws on conflict).
• Update: use dialect-specific MERGE/ON CONFLICT to update on conflict.
• Ignore: use IGNORE or dialect-specific syntax to skip conflicting rows.

Default (INTO)

Uses plain insert into; conflicts error out.

默认策略可以不指定，也可以明确设置

LambdaTemplate lambda = ...
int result = lambda.insert(User.class)
                   .applyEntity(user);
                   .onDuplicateStrategy(DuplicateKeyStrategy.Into) // explicit
                   .executeSumResult();

Replace (UPDATE)

Implementation depends on dialect, for example:

• MySQL: ON DUPLICATE KEY UPDATE clause on INSERT.
• Oracle: MERGE INTO ... WHEN MATCHED THEN ... WHEN NOT MATCHED THEN ....
• PostgreSQL: ON CONFLICT (...) DO UPDATE SET ....

提示

Dialect determines availability; forcing it without support will raise errors.

使用方式

LambdaTemplate lambda = ...
int result = lambda.insert(User.class)
                   .applyEntity(user);
                   .onDuplicateStrategy(DuplicateKeyStrategy.Update) // update on conflict
                   .executeSumResult();

Ignore (IGNORE)

Implementation depends on dialect, for example:

• MySQL: INSERT IGNORE.
• Oracle: MERGE INTO ... WHEN NOT MATCHED THEN ....
• DM: hint IGNORE_ROW_ON_DUPKEY_INDEX to ignore by PK.

使用方式

LambdaTemplate lambda = ...
int result = lambda.insert(User.class)
                   .applyEntity(user);
                   .onDuplicateStrategy(DuplicateKeyStrategy.Ignore) // ignore on conflict
                   .executeSumResult();