Review a little bit of knowledge in Oracle

Oracle 10g

Oracle is designed for Grid computing, the G in 10g refers to the grid computing

Oracle stores data in files, files that hold different information (data files, control files, log files) make up the physical structure of the database

Logical structure: Schema, extent, data block, segment

A collection of Schema database objects that, when created, generates a logical structure (table, view, index, clusters) that directly handles data with the same name as the user Schema,schema

View-Virtual, which can be viewed as a stored query that does not contain the knowledge to read data from the base table

Index-Provides access to table data to improve the efficiency of reading data

Cluster--The tables that share common columns are physically stored together to Cluster

Transaction:

Atomic: All statements are either executed or all canceled

Consistency: Cannot destroy DB integrity, all data should follow various constraints and rules in db

Isolation: Simultaneous operation, different transaction between non-interference

Durability: After successful execution, the results of all operations will be persisted

Some advanced queries:

DISTINCT: Eliminating duplicate rows

Null--condition is null, non-null--not is null

In--queries the row in the WHERE clause for its column values in the specified list. Not in

Between ... And ...--query column values in the WHERE clause to include rows within a specified range

Like--fuzzy query '% ', ' _ '% denotes 0 or more arbitrary characters, _ denotes an arbitrary character

Set operations: Combine multiple result sets into one result set

INTERSECT (intersection)--Returns the results shared by two queries

UNION All--Returns all records for the query containing duplicate records

UNION--All records that return a query do not contain duplicate records

Minus--a complement returns the remaining records after the first query record minus the second query record

Connection query: Inner JOIN, outer join (left OUTER join, right outer join)

(+) is an Oracle-specific connector that appears on the left side of the condition to represent the right outer join, which appears in the ZIP code to indicate the outer join

Subquery

For subquery, the main attention to any of the usage of any is encountered during the interview I just didn't think of it ... It's actually very simple.

Pseudo-column: ROWID, ROWNUM

RowNum can be used to implement database paging

Function:

Single-line functions: Character functions, numeric functions, conversion functions, date functions, NVL (x, Value), NVL2 (x, value1, value2)

Aggregate functions: SUM, AVG, COUNT, MIN, MAX

In fact, Oracle still has a lot of knowledge points and partition pagination what's the first to tidy up some very basic things slowly increase

Special thanks to Http://wenku.baidu.com/link?url=OFjIZA_ Tcmadbvudg9l8kq4bquochrbe7cqzvars9tsc6zrjvx5k2wwy8v5bicbruo9qs4l4gwz-pwek9bnpnnrza0vd0qyq6k0coijsbus

I looked at it when I was reviewing it, and it helped.