Database Administrator

In Oracle, The OBJECT_ID in the following table is the same as that in DATA_OBJECT_ID. However, the expression of DATA_OBJECT_ID after truncate changes. This feature can be used to determine whether the table has been truncate. Note: (database link,

When operating Oracle, if Oracle cannot be started or stopped normally, or Oracle import/export command execution is incorrect, It is usually caused by table space problems in Oracle instances. The following solution is taken from the network and is

Recently, I became the loyal fans of linus, And the linux lady was handsome. I found the feeling of Character Control. Installing linux in Oracle was a tough task, it took two days for free time. Share with you. First of all, it is a Linux package.

When creating a database table, you can specify a DEFAULT value (DEFAULT value ). Using default values for database fields helps isolate database design issues from application code. You can use the alter table command to change the default value of

I recently conducted a small test to import Oracle Data in the project to mysql and migrate data using mysql migration tool. After the migration, I found some data loss, check the Migration Report and find that max_allowed_packet has exceeded the

In many cases, you need to reference data other than the table to be updated in the expression. Like SQL server provides the update from clause, it can connect the table to be updated with other data sources. Although only one table can be updated,

Create table test ( NAME VARCHAR2 (2) ) Insert into test values ('test '); In Windows: In Windows, by default, VARCHAR2 (2) is equivalent to VARCHAR2 (2 BYTE). A Chinese Character occupies 2 bytes. In Linux: In Linux, by default, VARCHAR2

// In Oracle, we can view the object definition code from the data dictionary user_source (View;// Let's first look at the structure of the user_source View:Desc user_source;Name Type Nullable Default Comments-----------------------------------------

// Question:ID NAME------------11 Wang2 Zhao// Result:ID NAME--------1Wang2 Zhao// Solution 1:With t (Select 1 id, 'zhang 'name from dual union allSelect 1 id, 'King' name from dual union allSelect 1 id, 'lil' name from dual union allSelect 2 id,

// Data Ta Col_1 col_2 ----------- A B C D // Result: Col_1 col_2 ----------- A z0001 B z0002 C z0003 D z0004 // Create table ta ( Col_1 varchar2 (2 ), Col_2 varchar2 (7 )) / Insert into ta Select'A',''From dual union all

Instructions before installation:1. SUSE 10 is SUSE 10.1 Professional Edition (32-bit)2. Install "Developer" software, such as gcc, when installing SUSE.3. Here, the Oracle 10g's version is 10.2.0.1(32bit, and the installation package is

The details are as follows:Note the relationship between new. attribute and old. attribute and source table and view attributes.[Root @ me root] # su postgresBash-2.05b $ psql-E-h me.linux.edu.cn mydb1* ******** QUERY **********BEGIN; SELECT

This problem is caused by Oracle. One is that a dynamic execution statement appears in your program. In the process of dynamic execution, the object is invalid. The following program is still generated by static compilation. Its reference is still

Insert into reports an exception when inserting a record into the table, prompting: ORA-00928: missing SELECT keyword (missing SELECT keyword) Cause: 1. For example, most of the online expressions are similar because the column names cannot be

The following environments are: Software: HOST: winxp sp3 Virtual Machine Software: wmware ws 7.1 Virtual Machine System: rhel5.1 + mysql5.157 Host hardware: Cpu: Core 2 T8100 Memory: 3 GB Mysql> desc t; + ----------------- + ------------------- +

If you want to send an email from Oracle before 10 Gb, you must use the utl_smtp and utl_tcp feature packages of oracle to package an email sender program and then use it. since 10 Gb, this process will become very simple. because oracle provides us

Prerequisites:Mysql must enable the binary log functionBinary logs record DML DCL DDL [Mysqld]Log-bin =/data/mysql-bin Time Point 1 Thu Dec 16 13:53:54 CST 2010Create a tableInsert some dataMysql> use test;Mysql> create table upl (id int, user

The GROUPING function can accept a column and returns 0 or 1. If the column value is empty, GROUPING () returns 1; if the column value is not empty, returns 0. GROUPING can only be used in queries using ROLLUP or CUBE. GROUPING () is useful when a

When you use Database Link to integrate a remote Database, the system returns the ORA-22992 error when querying Blob fields from the remote Database. Some people use materialized views to solve this problem, but the synchronization mechanism of

Error message: Can't connect to local MySQL server through socket '/var/run/mysqld. sock' Solution: Create a mysqld directory under/var/run/, and create a link pointing to:/opt/lampp/var/mysql. sock Input command: ln-s/opt/lampp/var/mysql.