const ModelIncrementSchema = new Schema({ model: { type: String, required: true, index: { unique: true } }, idx: { type: Number, default: 0 } }); ModelIncrementSchema.statics.getNextId = async function(modelName, callback) { let incr = await this.findOne({ model: modelName }); if (!incr) incr = await new this({ model: modelName }).save(); incr.idx++; incr.save(); return incr.idx; }; const … Read more
For example, here’s a table that has a primary key but is not AUTO_INCREMENT: mysql> CREATE TABLE foo ( id INT NOT NULL, PRIMARY KEY (id) ); mysql> INSERT INTO foo VALUES (1), (2), (5); You can MODIFY the column to redefine it with the AUTO_INCREMENT option: mysql> ALTER TABLE foo MODIFY COLUMN id INT … Read more
You can leave your sort column equal to NULL by default. The only thing you need is a little smarter query. For instance: select * from something order by ifnull(sort, id)
Firebird 3 and later In Firebird 3 it is easy to create, as it introduced identity columns. In practice it is syntactic sugar for generating a sequence + trigger (as shown for Firebird 2.5) for you. For example create table t1 ( id integer generated by default as identity primary key ) Firebird 3 only … Read more
It is a GCC extension. In GNU C, addition and subtraction operations are supported on pointers to void and on pointers to functions. This is done by treating the size of a void or of a function as 1. If you add the -pedantic flag it will produce the warning: warning: wrong type argument to … Read more
Yes, you can do it like this: for (char alphabet=”A”; alphabet <= ‘Z’; alphabet++) { System.out.println(alphabet); } It is also possible with typecasting: for (int i = 65; i <= 90; i++) { System.out.println((char)i); }
The maximum number of INT in MySQL 4294967295 if you are creating 1000 threads per minute you would need 1440000 ( 1000 x 60 x 24 ) id’s per day. So you would run out of ids after about 8.17 years. The maximum number of BIGINT is 18446744073709551615 and that would be enough to create … Read more
I don’t think there is a way to bypass this behaviour of INSERT … ON DUPLICTE KEY UPDATE. You can however put two statements, one UPDATE and one INSERT, in one transaction: START TRANSACTION ; UPDATE pages SET etc=”randomness” WHERE name=”bob” ; INSERT INTO pages (name, etc) SELECT ‘bob’ AS name , ‘randomness’ AS etc … Read more
I had the same error but in my case I had about 1.5k records in the table. I fixed it by resetting the AUTO INCREMEN like that: ALTER TABLE `table_name` AUTO_INCREMENT = 1