Oracle

Database Administrators can have any tablespace online (online) (accessible) or offline (offline) (inaccessible) in the open (open) State of the database in addition to the SYSTEM tablespace (tablespace). The SYSTEM table space is always online when

Active session History ReportActive session HistoryV$active_session_ The history view provides information on extracting session activity at the instance level. The active session is sampled once per minute and stored in a circular buffer in the SGA.

When Oracle queries come with efficiency issues, we often need to understand the problem so that we can solve the problem. Oracle provides trace information for SQL execution, which contains textual information about SQL statements, some execution

Triggers are a technique that is provided by many relational database systems. In Oracle systems, trigger-like procedures and functions have a PL/SQL block that declares, executes, and processes exceptions.1. Trigger typeTriggers are stored as

? Describe the storage of table row data in a block? Create and manage table spaces? Get tablespace information How table data is stored When you create a table, you also create one that holds its data.segment。 A table space contains a

Hash joins (hash join) is a table join method in which two tables rely primarily on hashing to obtain a concatenated result set when making a table connection.For a sort merge connection, if the result set of the two tables is large and needs to be

When setting the environment variable, accidentally delete the path of the Oracle environment variable. When setting ODBC, add the DSN data source and the prompt "unable to load the oracle in oradb10g_home2 ODBC driverProgramBecause of system errors.

Listener. ora, tnsnames. ora, and sqlnet. ora are the three main files related to Oracle network configuration. They are all stored in the $ ORACLE_HOME \ Network \ ADMIN directory. Listener. ora is related to the database server, while tnsnames.

Background Software Programming in Jiri GA is fascinating: getting started with Database Transaction Processing (suitable for beginners)ArticleThe difference between ms SQL Server and Oracle in Database Transaction Processing caused some

The Blob field in Oracle is special. It has much better performance than the long field and can be used to save binary data such as sample slices. Writing BLOB fields is very different from writing other types of fields. Because blob itself has a

What is the Oracle character set? The Oracle character set is a collection of symbols for interpretation of byte data. It has different sizes and an inclusive relationship. Oracle supports the national language architecture, allowing you to store,

The database provides three field types: Varchar2, Blob, and Clob, which are used to store string or binary data. Varchar2 and Clob are used to store string data, while Blob is used to store binary data. Varchar2 is stored in a single byte and has

ORACLE alarm log file, oracle alarm Alarm log Introduction The alarm log file is a special trace file ). The alert log File is generally named alert _ . log, where SID is the name of the ORACLE database instance. Database alarm logs record

Oracle optimizer and SQL query execution sequence before Oracle executes an SQL statement, it first needs to check the SQL Execution Plan and then execute the SQL statement according to the execution plan, the optimizer executes the analysis of

Oracle may have this requirement to obtain the date after the specified working day. You want to obtain the specific date after the delay (excluding weekends and holidays) based on the start time and the number of days after the specified working

Dbms_stats Import and Export schema-level statistics are used in Oracle databases using the CBO optimizer mode. statistics are an important basis for CBO to generate the best execution plan. These statistics usually include column-level, table-level,

11.2.0.3.7 PSU patch upgrade Description: This is a new host that has not yet been created. If the database already exists, you need to perform the database refreshing operation! Environment: SUSE Linux Enterprise Server 11 sp1 (x86_64) requires

Database objects Common: tables: basic database objects for storing data, composed of rows (records) and columns (fields) Constraints: series of rules for performing data verification to ensure data integrity View: Logical display of data in a table

1. Static SQL and dynamic SQL Oracle compiler PL/SQL program blocks are divided into two types: one is the early compilation (early binding), that is, the SQL statement has been determined during program compilation, and most of the compilation

The ORACLE tutorial is to use and maintain the password file of the Oracle database. Summary: Oracle relational database system has been widely used for its excellent performance. Ensuring database security is an important part of database