SQL 如何在 SQLite 中添加默认值？
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How to add default value in SQLite?
提问by Azlam
I had a table modified to add status column to it in this fashion
我修改了一个表，以这种方式向它添加状态列
ALTER TABLE ITEM ADD COLUMN STATUS VARCHAR DEFAULT 'N';
However SQLite doesnt seem to add N to the column for any new ITEM created. Is the syntax wrong or is there any issue with SQLite and its support for defaults.
然而，SQLite 似乎没有为任何新创建的 ITEM 列添加 N。语法错误还是 SQLite 及其对默认值的支持有任何问题。
I am using SQLite 3.6.22
我正在使用 SQLite 3.6.22
回答by databyte
Looks good to me. Here are the Docs.
在我看来很好。 这是文档。
sqlite> create table t1 (id INTEGER PRIMARY KEY, name TEXT, created DATE);
sqlite> .table
t1
sqlite> .dump
PRAGMA foreign_keys=OFF;
BEGIN TRANSACTION;
CREATE TABLE t1 (id INTEGER PRIMARY KEY, name TEXT, created DATE);
COMMIT;
sqlite> alter table t1 add column status varchar default 'N';
sqlite> .dump
PRAGMA foreign_keys=OFF;
BEGIN TRANSACTION;
CREATE TABLE t1 (id INTEGER PRIMARY KEY, name TEXT, created DATE, status varchar default 'N');
COMMIT;
sqlite> insert into t1 (name) values ("test");
sqlite> select * from t1;
1|test||N
Dump your schema and verifythat your table structure is there after calling ALTER TABLE but before the INSERT. If it's in a transaction, make sure to COMMIT the transactionbefore the insert.
在调用 ALTER TABLE 之后但在 INSERT 之前转储您的架构并验证您的表结构是否存在。如果它在事务中，请确保在插入之前提交事务。
$ sqlite3 test.db ".dump"
