informix drop table if exists

INFORMIX uses the lock technology to solve the concurrency control problem of accessing the same object when multiple users access the database. INFORMIX supports complex and scalable locking technologies. Lock type INFORMIX has three different

Basic differences between oracle and informix 1: View tablespaces Selectb. file_name physical file name, B. tablespace_name tablespace, B. bytes/1024/1024 size M, (B. bytes-sum (nvl (. bytes, 0)/1024/1024 used M, substr (B. bytes-sum (nvl (. bytes, 0

The following is my ontape-r summary. I just share my experience (because I have seen this post in the Forum, but it is not very detailed) The whole process is only completed in a unique environment that I can access. If you have any mistakes,

I went to Microsoft for an interview this afternoon and was asked about the optimization of massive data queries. I am not sure how to answer the questions due to the small amount of application data I have developed and I am not very concerned

SQL Server is a relational database management system (DBMS) developed and promoted by Microsoft. It was initially developed by Microsoft, Sybase, and Ashton-Tate, the first OS/2 version was released in 1988. It is only one of many relational

Tables are divided into system tables and user tables.Database objects Tables (basic storage objects, composed of rows and columns), views (logical subset data obtained from one or more tables), sequences (unique serial numbers automatically

1NF: indicates that the columns in a table are atomic and cannot be decomposed. that is, the column information cannot be decomposed ,. In general, as long as the database is a comprehensive technology for Mysql database optimization technology, it

MySQL Database Basics1. Database system The database system is a kind of system that manages the array resources specially, the database stores one or more groups of processed data, the software that manages this database becomes the database

Abstr] "Sybase database does not support subqueries, so ......", We often hear this in database development. Is Sybase really true? Let's go to the sybase database to see which subquery statements are supported and not supported respectively. Hope

Transfer from http://www.cnblogs.com/qqzy168/p/3233817.html1. Fair use IndexAn index is an important data structure in a database, and its fundamental purpose is to improve query efficiency. Most database products now use the ISAM index structure