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Android GreenDao framework use basic articles
Android GreenDao framework use additions, deletions, revisions and investigation articles
The usage of queryBuilder can be executed through chain instructions, such as
testUserDao.queryBuilder().xx.xx.xx.结束指令。
Regarding the end instruction, as shown below
| method | Explanation |
|---|---|
| .list() | Query eligible data |
| .buildDelete().executeDeleteWithoutDetachingEntities() | Delete eligible data |
| .count() | Query the number of eligible |
Of course there are more than these, these are more common.
Regarding conditional query, GreenDao provides many methods
| method | Explanation |
|---|---|
| where | Query conditions (the conditions in where must all be met) |
| whereOr | Query conditions (if the conditions in where are met) |
| offset | Ignore the first n results of the query |
| orderAsc | Ascending |
| orderDesc | descending sort |
| … | … |
The following is the method in the conditional query
| method | condition |
|---|---|
| eq | == |
| notEq | != |
| like | Fuzzy query |
| between | Interval of two values |
| in | Range interval |
| notIn | Out of range |
| gt | > |
| lt | < |
| give | >= |
| the | <= |
| isNull | Is empty |
| isNotNull | not null |
example
testUserDao.queryBuilder().where(TestUserDao.Properties.Name.eq(name),TestUserDao.Properties.Age.eq(12)).list();
testUserDao.queryBuilder().whereOr(TestUserDao.Properties.Name.eq(name),TestUserDao.Properties.Age.eq(12)).list();
Whether it is where or whereOr, there can be one or more judgment sentences. The difference is that where is the relationship of "and", while whereOr is the relationship of "or".
QueryBuilder<TestUser> qb = testUserDao.queryBuilder();
List<TestUser> testUsers = qb.where(qb.and(TestUserDao.Properties.Name.eq(name),TestUserDao.Properties.Age.eq(12))).list();
QueryBuilder<TestUser> qb = testUserDao.queryBuilder();
List<TestUser> testUsers = qb.where(TestUserDao.Properties.Name.eq(name),qb.or(TestUserDao.Properties.Age.eq(12),TestUserDao.Properties.Age.eq(15))).list();
At the same time, you can also write complex statements in where and whereOr, so that you can implement multi-condition nested queries.