auto-increment | 易学教程

SQLite autoincrement - How to insert values?

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问题 I generate a SQLite table (in java): create table participants (ROWID INTEGER PRIMARY KEY AUTOINCREMENT, col1,col2); afterwards I try to add rows using the INSERT comand: insert into participants values ("bla","blub"); i get the error: java.sql.SQLException: table participants has 3 columns but 2 values were supplied I thought the row id would be generated automatically, but it seems that I miss anything. I tried another solution: PreparedStatement prep = conn.prepareStatement("insert into

Mapping PostgreSQL serial type with Hibernate annotations

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问题 I am using Hibernate 3.3 and PostgreSQL 8.x and would like to use Hibernate annotations to map an auto-incremented column which is NOT a primary key. It doesn't matter if the column is mapped using SERIAL type or sequences in Postgres as long as it gets auto-incremented by the database and not by Hibernate. I tried the following mappings, but they always generated null orderId. @Column(name = "orderId", insertable = false) @Generated(GenerationTime.INSERT) //@GeneratedValue(strategy = javax

What happens when auto_increment on integer column reaches the max_value in databases?

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问题 I am implementing a database application and I will use both JavaDB and MySQL as database. I have an ID column in my tables that has integer as type and I use the databases auto_increment-function for the value. But what happens when I get more than 2 (or 4) billion posts and integer is not enough? Is the integer overflowed and continues or is an exception thrown that I can handle? Yes, I could change to long as datatype, but how do I check when that is needed? And I think there is problem

How to fill in the “holes” in auto-incremenet fields?

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I've read some posts about this but none cover this issue. I guess its not possible, but i'll ask anyway. I have a table with more than 50.000 registers. It's an old table where various insert/delete operations have taken place. That said, there are various 'holes' some of about 300 registers. I.e.: ..., 1340, 1341, 1660, 1661, 1662, ... The question is. Is there a simple/easy way to make new inserts fill these 'holes'? thx Paulo Bueno What is the reason you need this functionality? Your db should be fine with the gaps, and if you're approaching the max size of your key, just make it unsigned

How to get last inserted row ID from WordPress database?

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问题 My WordPress plugin has a table with a AUTO_INCREMENT primary key field called ID. When a new row is inserted into the table, I'd like to get the ID value of the insertion. The feature is to using AJAX to post data to server to insert into DB. The new row ID is returned in the AJAX response to update client status. It is possible that multiple clients are posting data to server at the same time. So, I have to make sure that each AJAX request get the EXACT new row ID in response. In PHP, there

Derby Auto Increment by 100 when specified as 1

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问题 In used query to create derby database table consist of primary column auto increment. CREATE TABLE \"table\" (\n" + " \"id\" INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1) NOT NULL,\n" + " \"path\" VARCHAR(2000) DEFAULT NULL,\n" + " \"downloaded\" BOOLEAN DEFAULT false NOT NULL,\n" + " \"retried_times\" SMALLINT DEFAULT 0 NOT NULL,\n" + " \"name\" VARCHAR(40),\n" + " \"downloaded_date\" TIMESTAMP DEFAULT NULL,\n" + " PRIMARY KEY (\"id\")\n" When i insert a row

How to autoincrement versionCode in Android Gradle

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I'm experimenting with new Android build system based on Gradle and I'm thinking, what is the best way to autoincrease versionCode with it. I am thinking about two options create versionCode file, read number from it, increase it and write it back to the file parse AndroidManifest.xml, read versionCode from it, increase it and write it back to the AndroidManifest.xml Is there any more simple or suitable solution? Has anyone used one of mentiod options and could share it with me? I have decided for second option - to parse AndroidManifest.xml . Here is working snippet. task('increaseVersionCode

Auto increment in MongoDB to store sequence of Unique User ID

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I am making a analytics system, the API call would provide a Unique User ID, but it's not in sequence and too sparse. I need to give each Unique User ID an auto increment id to mark a analytics datapoint in a bitarray/bitset. So the first user encounters would corresponding to the first bit of the bitarray, second user would be the second bit in the bitarray, etc. So is there a solid and fast way to generate incremental Unique User IDs in MongoDB? Konstantin Pribluda You can, but you should not https://web.archive.org/web/20151009224806/http://docs.mongodb.org/manual/tutorial/create-an-auto

SQLite auto-increment non-primary key field

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问题 Is it possible to have a non-primary key to be auto-incremented with every insertion? For example, I want to have a log, where every log entry has a primary key (for internal use), and a revision number ( a INT value that I want to be auto-incremented). As a workaround, this could be done with a sequence, yet I believe that sequences are not supported in SQLite. 回答1: You can do select max(id)+1 when you do the insertion. For example: INSERT INTO Log (id, rev_no, description) VALUES ((SELECT

Defining Composite Key with Auto Increment in MySQL

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问题 Scenario: I have a table which references two foreign keys, and for each unique combination of these foreign keys, has its own auto_increment column. I need to implement a Composite Key that will help identify the row as unique using combination of these three (one foreign keys and one auto_increment column, and one other column with non-unique values) Table: CREATE TABLE `issue_log` ( `sr_no` INT NOT NULL AUTO_INCREMENT , `app_id` INT NOT NULL , `test_id` INT NOT NULL , `issue_name` VARCHAR