primary-key

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How to check if datatable.PrimaryKey is set

i have a datatable which i have to assign a primary key if it doesn\'t already have one. i tried : if (ds.Tables[0].PrimaryKey == null)[详细]

2023-03-03 03:01 分类：问答
Adding data to a table from the columns of auto-incremented primary keys of other tables

I have three tables: members, blobs, and contactlist. The members table is already populated with a primary key \'id\' (which is an auto-increment column). The blob table is already populated with a p[详细]

2023-03-03 00:00 分类：问答
What do you do when your primary key overflows?

We have a table, with an auto-increment int primary key, whose max value is now at the limit for the T-SQL int type. When we try to re-seed the table (because there are large gaps in the keys, nowhere[详细]

2023-03-01 03:26 分类：问答
MySQL query returns row 0 when it doesn't match the query criteria

I have开发者_如何学编程 a table with a primary key: Type:INT Length:11 Default:NULL Extra:auto_increment[详细]

2023-02-28 19:55 分类：问答
JPA: is it possible to change the PKs in an inheritance hierarchy?

I have the following DB design: (source: kawoolutions.com) As you can see States, Countries, and Continents are all sub tables of GeoAreas. The interesting fact here is that States and Countries ch[详细]

2023-02-28 02:05 分类：问答
how can I improve performance if I have used primary key on a guid column?

i got a table with half a million rows. the primary key is the guid column . I found the query select * from T wher开发者_运维问答e id =\'xxxx\' is very slow .[详细]

2023-02-26 19:32 分类：问答
What is the proper way to catch and handle ORA-00001 SQLException with JDBC?

I\'m creating a simple form that stores entered data in an extremely simple Oracle database table via a Java Servlet using JDBC.That table is using the email address as a primary key.If a user submits[详细]

2023-02-26 19:13 分类：问答
Constraint with Primary Key

Is there a difference between these two create table snippets? One includes CONSTRAINT keyword, other does not.[详细]

2023-02-26 10:10 分类：问答
Generate SQL JOIN statements

Background The following data is a specific example of a general problem (sorted by column name): Primary Key: as_comp.companynamecurrent.companyid[详细]

2023-02-26 02:35 分类：问答
Foreign key in oracle

I have created a table in oracle which has one FK that refers to 3 primary keys in 3 different table.But when I want to insert into it I see an error says parent key not found!what should I do?[详细]

2023-02-25 11:04 分类：问答