Database Administrator

The storage outline can be used to fix the SQL Execution Plan. The storage outline consists of a series of optimizer hints related to SQL statements. When the storage outline is available, oracle automatically generates an execution plan for the

This section describes the heap, extent, and chunk of the shared pool physical structure.Memory: The Shared Pool, large pool, and PGA are heap management.The shared pool is physically composed of many memory blocks. These internal blocks are called

I. DescriptionThe oracle exp/imp command is used to export/import databases; Data export: Exp myname/mypassword@192.168.100.152/orcl file = d: \ my. dmp -- export database fully exp myname/mypassword@192.168.100.152/orcl file = d: \ my. dmp full

Mysql database encoding layers: system layer, server layer, database layer, table layer, column layer, and client, connection, and result scenarios related to client communication; A character set is a set of symbols and encodings. A collation is a

Can the internal data be recovered when the hard disk breaks down? Recently, it was really a headache because the hard drive broke down. Fortunately, I met a great god and helped me solve the problem. I am very grateful to him for introducing this

For example, if you insert 1 million data records to a databaseSqlite3_exec (db, "insert into name values 'lxkxf', '24';", 0, 0, & zErrMsg );It will repeatedly Open and Close database files for 1 million times, so the speed will of course be slow.

1. Open the database:Note: To open a database, the file name does not have to exist. If the file does not exist, sqlite will be automatically created. The first parameter refers to the file name, and the second parameter is the defined sqlite3 **

1. ADO. NET Provider For SQLite.ADO. NET provider is provided by a company in Hong Kong (looks like). For the project address, see: http://sourceforge.net/projects/sqlite-dotnet22. encapsulate SQLite. NET and provide a simple operation help

SQLite IntroductionIn the introduction of System. data. SQLite is a single-host database management system similar to Access. It defines all databases (including definitions, tables, indexes, and data) are saved in a single file. In addition, SQLite

Copy codeThe Code is as follows:# Define SQLITE_ OK 0/* success | Successful result *//* Error code start */# Define SQLITE_ERROR 1/* SQL errors or database loss | SQL error or missing database */# Define SQLITE_INTERNAL 2/* Internal SQLite logic

In a (poor)PostgreSQLOnly a small modification is required in the query.(ANY (ARRAY [...]) to ANY (VALUES (...)))The query time can be reduced from 20 s to 0.2 s. From the simplest learning and useEXPLAIN ANALYZEStart from learning to useS

1. Relationship between original documents and entitiesIt can be a one-to-one, one-to-many, and many-to-many relationship. In general, they are a one-to-one relationship: an original document corresponds to only one entity. In special circumstances,

1. to automatically add fields, rewrite them. The automatically numbered field that is frequently used in access. After being imported to mssql, it is not an auto-incrementing int and needs to be set manually, change "no" of the Imported Automatic

How to connect to an access database remotely (such as through the Internet)Some time ago, many people asked how to connect to the access database remotely (such as through the Internet). I recently wrote an example to share with you:TCP/IP, ADO,

Table 1: Table 2:Id info id value1 a 1 102 B 2 303 c4 dWant to getId value1 10 // Table 2 exists2 20 // Table 2 exists3 0 // Table 2 does not exist4 0 // Table 2 does not existWhether an SQL statement can be used to solve the problem, instead of

Bosses:I have a query SQL statement. I hope to use an SQL statement to obtain the result. The problem is as follows:Table X:A B C D------------------Beijing Guangzhou 1000 10Beijing, Shenzhen 1200 20Beijing Shanghai 500 30Beijing, Tianjin, 300,

This evening, we found the difference between the two tables. Haha.Union concatenates two tables and deletes their repeated items;Union all does not delete the duplicate items of the two tables.This is simple. But also record it. It is a small

If the two conditions are met, the standardization level of the database is still relatively high. Of course, these are two general indicators. To meet the requirements of database design standardization, the following five requirements must be

Today, a buddy sent a request for help, saying that the master node was never synchronized. He sent an error message to the master node and found that the error message from the error log was not truncated to show slave status \ G ), however, when

This article introduces how to monitor mysql with fixed port 3306. I. Client 1. Add it to/usr/loca/zabbix/conf/zabbix_agentd.conf. UserParameter=mysql_3306[*],mysql -h localhost –P 3306 -uzabbix -pzabbix -e "show global status"|grep "\"|cut –f2 If