ERROR: type "smallserial" does not exist LINE 2: ...llserial" TYPE smallserial USING "o_smallserial"::smallseria...

这个错误通常是因为使用了PostgreSQL数据库的版本太旧，不支持smallserial数据类型。建议升级到PostgreSQL 10及以上版本，或者使用其他支持该数据类型的数据库。如果您已经在较新版本的PostgreSQL中使用了smallserial类型，可能是因为您的数据库架构比较复杂，需要检查您的SQL语句是否正确。

相关问题

ERROR: type "serial" does not exist LINE 2: ...ALTER COLUMN "o_serial" TYPE serial USING "o_serial"::serial

这个错误通常是因为使用的数据库不支持serial类型。Serial类型在PostgreSQL中是一种自增类型，可以自动增加数字。如果您使用的是MySQL等其他数据库，那么它可能没有这种类型。建议在使用之前先检查您的数据库是否支持serial类型。如果您确认您的数据库支持serial类型，那么可能是因为您在执行ALTER COLUMN语句时使用了不正确的类型名称，建议检查您的SQL语句是否正确。

java.lang.IllegalArgumentException: column '_id' does not exist

This error message is thrown when a query is executed on a database table that does not contain a column named '_id'. In Android, the '_id' column is a required column for all tables that are used with CursorAdapter and other similar classes.

To fix this error, you should ensure that your database table contains an '_id' column. This column should be defined as an integer primary key autoincrement. You can create this column by adding the following line to your CREATE TABLE statement:

CREATE TABLE my_table (_id INTEGER PRIMARY KEY AUTOINCREMENT, column1 TEXT, column2 INTEGER, ...);

If you already have a table that does not contain an '_id' column, you can add it using the ALTER TABLE statement:

ALTER TABLE my_table ADD COLUMN _id INTEGER PRIMARY KEY AUTOINCREMENT;

Once you have added the '_id' column to your table, you should be able to execute queries without encountering the IllegalArgumentException.