Oracle

Complete deletion of Oracle databases under Linux OS details: 1. Turn off Oracle server and background processes Ps-ef | grep ora Shut down the database. Shutdown immediate 2. Turn off the monitor. Lsnrctl status If it's open, execute Lsnrctl

Most recent projects require bulk operations, the client passes a comma-delimited set of ID strings to the database, and the stored procedures need to be split and processed individually. There are several ways to deal with the past: 1, write the

Note the point: 1. If open in Pl/sql and other tools, directly modify the following code [Italic bold section] to perform 2. To ensure that the path exists, such as "D:\oracle\oradata\Oracle9i\" is the path you want to save the file exists /* is

1. Install the required patch pack for the oracle11g, install the CD-ROM on all, access to the CD's server directory: (preferably through Oracle's official documentation to determine which packages need to be installed) 2. Modify the user

When you write a stored procedure, you use the following SQL statement Copy Code code as follows: SELECT MAX (re_date) into v_re_date From t_recording WHERE ID = ' 100010010102 ' Logically, the result of a query based on this

Round (X[,y]) "Function" returns the rounded value Parameter x,y, numeric expression, if Y is not an integer, intercepts the y-integer portion, if y>0 is rounded to Y-decimal, and if Y is less than 0, rounded to the decimal point to the left. "Back"

Applicable situation : When Oracle sorts query results, the sorted field has a null value and you want to specify a null value to be at the front or the last side keyword : Nulls first;nulls Last Default: null defaults to Maximum value (that

The more typical problems are: Sometimes, it indicates that Ming has indexed, but the query process obviously did not use the relevant index, resulting in a lengthy query process, a huge resource, the problem in the end is where? Search in the

1. DIRECTORYSpecify the directory where dump files and log files are located Directory=directory_object Directory_object is used to specify the directory object name. Note that directory objects are objects created using the Create DIRECTORY

In this case, if there is duplicate data in the temporary table, whether the primary key field is BUSINESSID, or if a whole row has duplicates, it will report a violation of the unique PRIMARY KEY constraint error. Method: Group BY XX has count (*)

stored procedures and stored functions refer to subroutines stored in the database for all user programs called stored procedures, stored functions。 The stored procedure does not return a value. Stored function has return value Creating a stored

UPDATE 1, the first backup data (security, improve performance). 2, batch update, small batch submission, to prevent the lock table. 3, if the updated automatically indexed, the amount of updated data is very large, the first to cancel the

1. Query the current process of the database number of connections: Copy Code code as follows: Select COUNT (*) from v$process; 2. View the number of connections for the current session of the database: Copy Code code

Methods one, using Sql*loaderThis is a more used method, provided that the destination table in the Oracle data already exists. The overall steps are as follows:1, save the Excel file as a new file, such as file name Text.txt, file type selected

1. Optimize the application and business logic, this is the most important. 2. Database design phase paradigm and the flexible application of the inverse paradigm. In general, for frequently accessed but infrequently modified data, internal design

There are several types of tables in Oracle:1, the heap organization table (heap organized tables):Commonly used table types, managed in heaps, use the first free space in the segment to fit the data size when data is added, and when data is deleted,

Number data type Number (precision, scale)A) precision represents a valid bit in a number, and Oracle uses 38 as the precision if no precision is specified. b If the scale is greater than 0, the number is accurate to the number of digits to the

The lag and lead functions can fetch the first n rows of data from the same field and the values of the latter n rows in a single query. This can be done using table joins to the same table, but with lag and leads is more efficient. Copy Code

There are several modes of locking in Oracle:0:none1:null Empty2:row-s row Sharing (RS): Shared table Locks3:row-x line-specific (RX): For line modifications4:share shared Lock (S): block other DML operations5:s/row-x shared row Private (SRX):

Parsing Oracle's method for select locking and query for locksOracle to select Lock method Copy Code code as follows: CREATE TABLE Test (a number,b number); INSERT into test values (1,2); INSERT into test values (3,4); INSERT into test