sql primary key autoincrement

The ORA exception was encountered today when a unique index was established on an existing table Ora-02437:cannot Validate (primary KEY or UNIQUE key constraint name)-PRIMARY key violated The data for a primary

NULL,Operation_time datetime default NULL,Logrecord_operation varchar (+) default NULL,PRIMARY KEY (logrecord_id),KEY Wh_logrecord_user_name (USER_NAME))Key is an index constraint that constrains the index of a field in a table by primary foreign unique. Common with foreign

Rimary key database PRIMARY KEY constraint Database PRIMARY KEY constraintThe PRIMARY KEY constraint uniquely identifies each record in a database table. The

There are multiple tables in the PostgreSQL database test environment that do not have a PRIMARY KEY constraint and only one serial field. Now you need to add to the table with no primary key, the field ID of the serial type. First, how do I find out which tables in the PostgreSQL database do not have

"PHP" MySQL gets the primary key for inserting data (self-increment id), MySQL primary key To prevent primary key collisions, the self-increment (auto_increment) field is often used when designing db. So before inserting the dat

In a large application, if you need more than two sets of databases (such as SQL Server and Oracle), Can You encapsulate all the required SQL queries in the stored procedure, in this way, you only need a set of access code. Is there a better solution to this problem? It is easy to directly use guid as the primary key

Oracel ALTER TABLE adds a primary key to the table primary key Sql>Sql> CREATE TABLE EMP (empno number (4) is not NULL,2 ename varchar2 (10),3 Job Varchar2 (9),4 Mgr Number (4),5 HireDate Date,6 Sal Number (7, 2),7 Comm Number

generated by the data. Create a member table using the following SQL statement:/* Create the mysql5.0 table member */Create Table member (Id int not nullAuto_increment,/* Primary Key automatically generated by the database */Name varchar (100),/* member name */Email varchar (255),/* Email */Primary

auto-incrementing primary key. Before using PHP to insert data, I imported some data, similar to the following: 1 xx 2 ss 3 rr Then insert it in PHP. After multiple inserts, it is as follows: 1 xx 2 ss 3 rr 4 ww 1 xx 2 ss 3 rr 5 ee 4 ww 1 xx 2 ss 3 rr 6 tt 5 ee 4 ww However, after I only import the table structure, it is normal to use PHP to insert it. However, at the time of insertion, the id does not

Oracle primary key deletion, joint primary key Creation1. Delete the primary key alter table tablename drop PRIMARY_KEY execute the preceding SQL statement to delete the

1. Delete the primary key ALTER table TABLENAME drop primary_key Run the above SQL to remove the primary key; Assuming that the ALTER TABLE TABLENAME drop CONSTRAINTS COLUMN Cascad is not successful E --delete constraint alter TABLE TABLENAME DISABLE Primary_column; --Set th

-the proxy primary key.From a practical standpoint, any entity attribute is likely to change. Such as: The Customer Information table using 8-digit customer number as the primary key, but the user business expansion, 8 for the encoding is not enough to use, it is necessary to adjust the primary

Hibernate primary key generation policy and hibernate primary key policyThe All generators implement the org. hibernate. id. IdentifierGenerator interface. This is a very simple interface; some applications can choose to provide their own specific implementations. Of course, Hibernate provides many built-in implementat

The Oracle view does not have a primary key by default. Therefore, when you use hibernate to generate a java class in reverse direction, a composite primary key is automatically used to generate a class with the class name + ID, which makes it difficult for later development. The Oracle view does not have a

the next, such as: + GG +-II How do you make it start from 0? (Or is it 1?) ） Really do not want to waste points, my problem is more, points or save a bit of it. If there is a satisfactory answer I will add points, if it can be fully resolved I will add 80 points, including the direct deletion of the phpMyAdmin database in the table records will not be a problem. ------Solution-------------------- Run SQL: ALTER TABLE ' Your table name ' Auto_incre

[PHP] MySQL obtains the primary key (auto-increment ID) and mysql primary key of the inserted data. To prevent primary key conflicts, auto-increment (auto_increment type) fields are often used in DB Design. Therefore, the

id 7-11, corresponding to the number of SQL statements for inserting data. Because we have not submitted the file, this result can only be seen in client 2. Here we can see that the auto-increment primary key is globally unique. If a transaction is rolled back, the auto-increment part will not be affected. The auto-increment

. However, at the time of insertion, the id does not start from 0, but is a relatively large number. it should be the next of the last id used, as shown in the following code: 40 gg 41 ii How can we make it start from 0? (Or 1 ?) I really don't want to waste points. I have a lot of problems. I 'd like to save some points. If there is a satisfactory answer, I will add points. if it can be completely solved, I will add 80 points, including directly deleting the records in the table in the phpmya

'AUTO_INCREMENT = maximum number; This idea is basically not practical. The following describes a convenient method. If a Mysql primary key has a value during insert, auto-increment is not used. That is to say, when inserting data, you only need to add the ID by yourself, and then perform auto-increment according to the number of inserts. This number is assigned by your own logic judgment code, as long a

, MESSAGE VARCHAR (255) NOT NULL, PRIMARY KEY (ID) } The primary key generation policy for identity types in JPA is as follows: @GeneratedValue (strategy=generationtype.identity) @Column (name= "id") private long ID; Because the primary