Database Administrator

-- 1. This statement is equivalent to a Left join statement. The where clause is the number of updates. -- Note! If the number of rows in the table (obtained after where) is smaller than that in the outer table (obtained after where), a record that

Database Version:SQL> select * from v $ version;BANNER----------------------------------------------------------------Oracle9i Enterprise Edition Release 9.2.0.1.0-ProductionPL/SQL Release 9.2.0.1.0-ProductionCORE 9.2.0.1.0 ProductionTNS for 32-bit

No one wants to lose the key to the house, but no matter how careful or long, such a thing will always happen several times. The same is true for MySQL passwords. It is not safe to write them in documents, and it will inevitably be forgotten in your

The SQL statement exported by MySQL may be very slow during import. Using several parameters properly during export can greatly speed up the import. -E uses the multiline INSERT syntax that includes several VALUES lists;-Max_allowed_packet =

Test environment: Oracle 10g 1. method 1 MD5 Encryption Create Or Replace FunctionFn_md5 (input_string VARCHAR2)ReturnVarchar2 IS Raw_input RAW (128): = UTL_RAW.CAST_TO_RAW (input_string ); Decrypted_raw RAW (2048 );

When installing Oracle on the command line, the rpm package in the configuration file will not be repeat, and the problem is not very serious. Several problems will be encountered. 1. If your machine is red-hat 5.6 and Oracle 10g only recommends 3

1. Update a single table Syntax: update test set column = value [, column = value]... [where condition] Eg: select * from test Eg: update test set sex = 111 Translation: update the sex column of the entire table to 111 Eg: update test set sex = 3

The database cannot use the archive logs of Oracle when the set limit value is reached. The error message is: ORA-00257: archiver error. Connect internal only, until freed At this time, you can choose to move its log file to another place, and

The Iterate label of Ibatis can be used to traverse every element of the List cyclically to form an SQL file dynamically. But how can I use Iterate to traverse a nested List, after a lot of experiments, I finally found this method. The Code is as

Oracle has been in use for a long time, and many new users and tablespace are added. You need to clear them. For a single user and tablespace, you can use the following command. Step 1: delete a user Drop user ××cascade Note: If a user is deleted,

During the top Shard, The PreparedStatement encountered garbled Characters During database storage, which had plagued the database for a long time and finally solved the problem. The problem code is as follows: Pstmt = con. prepareStatement

You can use the Change command to Change the string (that is, replace the string ). Syntax: C [HANGE] sepchar old [sepchar [new [sepchar] Sepchar is the separator, which can be "/" or "!" -- Special attention Old string New String For example,

Now we are all-around. We have to be familiar with Oracle for Java. We need to test an application yesterday, so we need to have a database. We cannot test it in the production environment. So let us know over there, first, export the data of the

Oracle 11.2.0.2 has many bugs.Many databases have encountered problems after being migrated to Oracle 11.2.0.2.Two Oracle 11.2.0.2 problems are being resolved:ORA-00600: internal error code, arguments: [ktecgsc: kcbz_objdchk], [0], [0], [1], 2. This

1. Perform the delete operation.SQL> drop table t;Table dropped.SQL> select * from tab;TNAME TABTYPE CLUSTERID-----------------------------------------------BIN $ wWGJJd0UCrDgRAAMKRcWyg = $0 TABLETTS SYNONYMTTSS SYNONYMSQL> purge table t;Table

We have the following requirement: create two users in the database. User A creates some views and directly accesses the tables in one mode in the database, and access tables in other databases through the database link. Another user B can access

About GoldenGateOracle Golden Gate is a log-based copy and backup software for structured data. It parses online logs of the source database or archive logs to obtain incremental data changes, apply these changes to the target database to

Our application developers found that the execution time of an SQL statement when binding a variable is much slower than when not binding a variable, even slowed down to dozens of times. In the application, if the executed SQL statement is not bound

The SQL statement exported from MySQL may be very slow during import. It took nearly three hours to import only 0.45 million records. Using a few parameters properly during export can greatly speed up the import. -E uses the multiline INSERT syntax

Oracle Server modifies Character Set and uses dba user to log on 1. view the character set of the current serverSelect userenv ('language') from dual; 2. Shut down the databaseShutdown immediate; 3. Start to MountStartup mount; 4. Session