Common oracle system tables

Common oracle System Table 1. SQL-based common system Table 1.1. system Object table sysobjects www.2cto.com Function Description: stores the objects of the current database, such as constraints, default values, logs, rules, stored procedures, and other important fields. Explanation: sysObjects (Name sysname, -- object Name id int, -- object id xtype char (2), -- object type char (2), -- Object type (exactly the same as xtype? A little depressing ...) Uid smallint, -- ID of the object owner ...... -- Other fields are not commonly used. Note: The xtype and type are exactly the same, and their data is: C = CHECK constraint D = DEFAULT value or DEFAULT constraint F = foreign key constraint FN = scalar function IF = nested table function K = primary key or UNIQUE constraint L = Log www.2cto.com P = Stored Procedure R = rule RF = copy and filter Stored Procedure S = system table TF = table function TR = trigger U = User table V = view X = extended stored procedure the table contains all objects in the database, if there is information such as the table Stored Procedure view 1.2. database field table sysColumns Function Description: all fields in the current database are retained. Description of important fields: sysColumns (name sysname, -- field name id int, -- ID xtype tinyInt of the table to which the field belongs, -- this field type, associated with the length smallint of the policypes table, -- physical storage length of this field ...... For example, if you want to query a table that contains those fields and the length of these fields is 1.3, the system group of the current database of the System user table sysUsers, and the user. SysUsers (uid smallint, -- User ID name smallint, -- name uid varbinary (85), -- belongs to a login ...... Manage the dependencies of the current database 1.4. sysdenpends. For example, when I want to modify a structure, I am afraid that the modification will affect the stored procedure of other view functions. This can be queried before modification. The view function stored procedures that call this table can be modified after modification. Generally, the system tables used by programmers, basically, these other special system tables (mainly in master or tempdb) are included. common DBA tables 2.1. dba_users Database User Information dba_segments table segment information dba_extents data zone information dba_objects database object information dba_tablespaces database tablespace information partition Data File Settings information dba_temp_files temporary data file information rollback segment information Login User table space quota information dba_free_space database idle space information dba_profiles database user resource restriction information dba_sys_privs user's system permission information dba_tab_privs user's object permission information dba_col_privs user's column object permission information role user's role information dba_audit_trail audit tracking information dba_stmt_audit_opts audit settings information dba_audit_object Object audit results information dba_audit_session session audit results information dba_indexes user mode index information 2.2. user_objects user object information user_source all resource Object Information user_segments user table segment information user_tables user table Object Information user_tab_columns user table column information user_constraints user object constraint information user_sys_privs current user's system permission information user_tab_privs current user's object permission information user_col_privs current user's table permission information user_role_privs current user's role permission information user_indexes user's index information user_ind_columns user's index information user_cons_columns table column information corresponding to user constraints user_clusters all user cluster information user_clu_columns user's cluster information user_cluster_hash_expressions information of the hash cluster 2.3. v $ database information v $ datafile data file information v $ controlfile Control File Information v $ logfile redo log information v $ instance database instance information v $ log group information v $ loghist log history information v $ sga database SGA information v $ parameter initialization parameter information v $ process database server process information v $ bgprocess database background process information v $ controlfile_record_section information of each part of the control file v $ thread information v $ information recorded in the datafile_header data file header v $ archived_log archive log information v $ archive_dest configuration information v $ logmnr_contents dml ddl result information for log analysis $ dictionary file information for logmnr_dictionary Log Analysis v $ log list information for logmnr_logs Log Analysis v $ tablespace information v $ tempfile temporary file information v $ filestat data file I/O statistics v $ undostat Undo data information v $ rollname online rollback segment information v $ session information v $ transaction information v $ rollstat rollback segment statistics v $ pwfile_users privileged user information v $ sqlarea resources accessed by the currently queried SQL statement and Related Information v $ SQL and v $ sqlarea are basically the same related information v $ sysstat database system status information 2.4. all _ starts with all_users all user information of the database all_objects all object information of the database all_def_audit_opts all default audit settings information all_tables all table Object Information all_indexes all database object indexes information 2.5. session _ start with session_roles session role information session_privs session permission Information 2.6. index _ starts with index_stats index settings and storage Information 3. view the current date, time SQL> select sysdate from dual; SYSDATE -- 18-3-01 SQL> select to_char (sysdate, 'yyyy-mm-ddhh24: mi: ss') from dual; TO_CHAR (SYSDATE, 'yy --- 22:37:56 as a calculator using SQL> select 1 + 2 from dual; 1 + 2 -- 3 view the sequence Value SQL> create sequence aaa increment by 1 start with 1; SQL> select aaa. nextval from dual; SQL> select aaa. nextval from dual; NEXTVAL -- 1 SQL> select aaa. currval from dual; CURRVAL --