queries: conjunction (AND), disjunction (OR), difference (-)

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Criteria and DetachedCriteria and use the difference between

Criteria and DetachedCriteria the main difference is in the form of creation is not the same, Criteria is online, so it is a Hibernate Session to create; and DetachedCriteria is offline, when you need to create Session, DetachedCriteria provides two stati

Postgre in the intersection. And. Difference set methods

The results of two queries can set operations, intersection, difference combination. The syntax is query1 UNION [ALL] query2 query1 INTERSECT [ALL] query2 query1 EXCEPT [ALL] query2 query1 and query2 are using all the queries that we stop here to dis

The usage of Hibernate in the Criteria

Hibernate is designed CriteriaSpecification as a parent Criteria interface is provided below the Criteria and DetachedCriteria. Criteria and DetachedCriteria The main difference is not the same as the form is created, Criteria is online, so it is carried

Hibernate - DetachedCriteria the full use of

Recent projects developed using Spring and Hibernate, feeling Criteria relatively easy to use, in the query method   Design Criteria can be flexible according to the characteristics of easily query assembly. Now the usage of Hibernate's Criteri ...

Full use of Criteria

Hibernate - DetachedCriteria the full use of Recent projects developed using Spring and Hibernate, feeling Criteria relatively easy to use, in the query method   Design Criteria can be flexible according to the characteristics of easily query assembly.

hibernate in the application of Criteria and CriteriaSpecification

Design Criteria can be flexible according to the characteristics to easily query the assembly. Now the usage of Hibernate's Criteria to sum up: Hibernate Criteria designed CriteriaSpecification as the parent interface, the following provides the Crite

hibernate fuzzy query (dynamic add query)

Hibernate Criteria was designed as a parent CriteriaSpecification interface provides the following Criteria and DetachedCriteria. Criteria and DetachedCriteria The main difference is not the same as the form is created, Criteria is online, so it is c

Criteria and application of the distinction and Detachedcriteria

Hibernate Criteria was designed as a parent CriteriaSpecification interface provides the following Criteria and DetachedCriteria. Criteria and DetachedCriteria The main difference is not the same as the form is created: Criteria is online, so it is carrie

Hibernate Criteria usage

Recently in a project using Spring and Hibernate to develop, feeling Criteria relatively easy to use, the query method  Design Criteria can be flexible according to the characteristics of the query to be easily assembled. Now the usage of the Hibern

[4] MongoDB redundancy Cluster (Replication)

Redundancy MongoDB Cluster (Replication) Advantages: 1: Mongo is a JSON document-oriented database, is designed as a real object database, rather than a pure key / value store. 2: MongoDB suitable to describe the characteristics of an individual enti

The stability of stored procedures and the impact on the index

Each function has a volatile level (VOLATILE, STABLE, IMMUTABLE). If there is no clear statement CREATE FUNCTION command areas, then, VOLATILE is the default. Volatile area is to optimize the device acts as a commitment on the function: VOLATILE can

mysql left (right) join on and where to use different screening

Have such a problem with mysql in mysql query left (right) join in on and filter the data where the query whether there are differences. May only be looking at two keywords do not see any problems. Then we use the actual example in the end there is n

hibernate in the use of a Criteria query package

Criteria can be flexible according to the characteristics of query assembly. Can easily increase the number of query, set the sort to achieve paging. Criterion is the Criteria of the query. Criteria provides add (Criterion criterion) method to add the que

Storage stability of the procedure and the impact on the index

Each function has a volatility level (VOLATILE, STABLE, IMMUTABLE). If there is no clear statement CREATE FUNCTION command areas, then, VOLATILE is the default. Volatile areas of the optimizer, a commitment to act on the function: VOLATILE can do any

Start with ... Connect By clause recursive queries are generally used for a table maintenance application of tree structure

Start with ... Connect By clause recursive queries are generally used for a table maintenance application of tree-like structure. Create a sample table: CREATE TABLE TBL_TEST ( ID NUMBER, NAME VARCHAR2 (100 BYTE), PID NUMBER DEFAULT 0 ); Insert test data:

Inline tables in the database. Outreach. What the right has linked the difference?

Inline : a inner join b on a.id=b.id Two tables are existing ID record Left outer : a left join b on a.id=b.id As long as the table a id, Table a ,b There is no b field NULL The right outreach : a right join b on a.id=b.id As long as the table b reco

Sequence of SQL Queries

The previous section, we explain the basic queries and query terms, think for basic queries and the query is relatively simple conditions, to be described below for the ORDER BY clause is not very difficult, as long as we master the use of the variou

hibernate mode to save the difference between the various

=========================== hibernate for update and merge First, merge the role roughly equivalent to saveorupdate this method, which has a unique sexual identity, then run the save, do not you run the update The following comparison of the difference be

There are those who jdk1.4 and jdk1.5 difference (more detailed the better)?

There are those who jdk1.4 and jdk1.5 difference (more detailed the better)? Not much difference, as long as you are careful not to use outdated methods on the line , If the new version added or changed methods, docs will say in , In the method explained

Session of the get () and load () the difference between

[size = xx-small] [/ size] Hibernate data loading --Session.get/load Session.load / get methods are based on the specified entity class and id to read records from the database, and returns with the corresponding entity object. The difference is: 1. ...

C #, the difference between const and readonly (change)

C # introduced the readonly modifier to indicate read-only domain, const to represent the same constant. By definition of the read-only domain can not write, the same constant can not be modified, both in the end what is the difference? Read-only dom ...

sql exist and in the difference in the

There are several claims: 1. Exist efficient than in the high, all in all should be replaced with the exist 2. Outer little use in in, outside a small inner Dayong exist 3. Outer used within the small exist, outside a small inner Dayong in 1:00 can n ...

Oracle SQL statement (join queries)

1, internal connections and external connections within the connection <br /> return to satisfy the connection conditions for the record; suits the connection is connected within the extension, which will not only satisfy the connection conditi ...

oracle of the difference between functions and stored procedures

One, oracle of the difference between functions and stored procedures? A: function must return a value, while the process does not return value. B: function can be carried out separately, but the process must execute the implementation. C: function can be

C # const and readonly difference (change)

C # introduced the readonly modifier to indicate read-only domain, const to represent the same constant. By definition of the read-only domain can not write, the same constant can not be modified, both in the end what is the difference? Read-only dom ...

The difference between stored procedures and functions

Essentially no difference. Only a function like: Returns a variable limit. The stored procedure can return multiple. The function is embedded in the sql can be used, you can select the call, while the stored procedure not work. Implementation of the ...

oracle table were obtained from the intersection of the two difference sets of issues

1, intersect operation returns query results in the same part of the intersection of both their SQL> select * from abc 2 intersect 3 select * from abc2; 2, minus operator returns the query results in the first and second query results are not the ...

The difference between IN and EXISTS

and exists in the differences and the efficiency of SQL In this paper, the difference between in and exists with the SQL implementation of the efficiency of the overall order of ... ... Recently began to many forums to discuss the difference between in an

The difference between stored procedures and functions (2)

Essentially no difference. Only a function like: Returns a variable limit. The stored procedure can return multiple. The function is embedded in the sql can be used, you can select the call, while the stored procedure not work. Implementation of the ...

Joint Optimization of SQL queries to replace the union with the union all

To replace the union with the union all Optimizing UNION UNION has an interesting optimization that exists across a few different databases. It's obvious when you think about how it works. UNION gives you the rows from two tables that don't exist

oracle multi-table queries Statistics Section of the function of the joint order by having sub-query set operations

Joint multi-table query by connecting to a multi-table queries, multi-table query data can come from multiple tables, but the table must have an appropriate connection between the conditions. In order to query from multiple tables, you must identify the p

How to improve website efficiency of large data queries (Reprinted)

How to improve website efficiency of a large amount of data query Taken from: http://clglctm.blog.hexun.com/26073206_d.html Abstract : At present, information technology companies are carried out in full swing among companies in the rapidly expanding amou

oracle9i.10g.11g difference

Recently resigned today, just interview a company posts the data analyst. Beginning the interview, one aspect is still relatively satisfied with the final technical director of that company asked me often oracle more familiar with that version, I said, 9i

Collection List Set and Map Use and the difference between

Collection interface interface object collection ├ List sub-interfaces can be saved by access has ordered repeat │ ├ LinkedList class interface does not sync to delete the thread into the list of unsafe │ ├ ArrayList class array of random access interface

load () and get () the difference between

load () and get () the difference between Session.load / get methods are according to the specified entity class and id to read records from the database and return the corresponding entity object. The difference is: 1. If you can not find the record

EXISTS.IN.NOT EXISTS.NOT IN and performance analysis of the difference between

1.EXISTS the implementation of the process select * from t1 where exists (select null from t2 where y = x) Can be understood as: for x in (select * from t1) loop if (exists (select null from t2 where y = xx) then OUTPUT THE RECORD end if end loop In

oracle connect by prior implementation of recursive queries

Start with ... Connect By clause recursive query for a table to maintain the general application of tree structure. Create a sample table: CREATE TABLE TBL_TEST ( ID NUMBER, NAME VARCHAR2 (100 BYTE), PID NUMBER DEFAULT 0 ); Insert the test data: INSERT IN

difference between db2 and oracle base sql

1. Fetch the first N records Oracle:Select * from TableName where rownum <= N; DB2:Select * from TableName fetch first N rows only; 2. Get system date Oracle:Select sysdate from dual; DB2:Select current timestamp from sysibm.sysdummy1; 3. Null Conversi

The difference between OPEN_CURSORS and SESSION_CACHED_CURSORS

Open cursors Open cursors take up space in the shared pool, in the library cache. To keep a renegade session from filling up the library cache, or clogging the CPU with millions of parse requests, we set the parameter OPEN_CURSORS. OPEN_CURSORS sets

How to speed up queries

How to speed up queries? 1, upgrade the hardware 2, according to query, indexing, index optimization, optimizing access to restrict the result set of data. 3, expanding the server memory 4, increasing the number of server CPU 5, for large databases do not

[PHP] PHP in the include () and require () the difference between

This carried over: http://hi.baidu.com/ckcljj/blog/item/9518e103c1cec17f3912bbb1.html Today to see php documentation, see the difference between include and require explanation, feel this is a very easy for beginners to confuse the place in this reco

Oracle SQL in the difference between IN and EXSITS Summary

IN Determine whether a given value or subquery match the value in the list. EXISTS Specify a subquery to detect the presence of line. Compare EXISTS and IN query This example compares the two semantics similar to the query. The first query uses EXIST

difference between hql and sql

1.hql and the difference between sql sql queries for the database table Object-oriented query hql hql: from the back with the class name + class object where the object's properties to do after the conditions sql: from followed by the use of the table

The difference between stored procedures and functions (Reprinted)

Essentially no difference. Only a function like: Returns a variable limit. The stored procedure can return multiple. The function is embedded in the sql can be used, you can select the call, while the stored procedure not work. Implementation of the

Difference between overloading and override

Difference between heavy and sometimes covering the class of the same function has a variety of ways, in the end achieved by that method, the caller depends on the given parameters. For example, teachers can train animals, acrobatics, for different animal

ibatis batch processing + multi-table queries Relevance

ibatis batch operations ibatis batch operation there are two ways: One is directly in the code to loop operation, the other is in the configuration file for loop operations. (1) loop in the configuration file: 1. The situation one: more input parameters A

The difference between stored procedures and functions (transfer)

Essentially no difference. Only a function like: can only return a variable limit. The stored procedure can return multiple. The function is embedded in the sql can be used, you can select the call, and stored procedures can not. Implementation of th

Order to form queries using SQL

Desc table shows the structure of all records in the data table query select * from table Some of the fields for all records query: select field name 1, 2 from data table field names select name, age from certain fields of data query different records: se

Queries, you need to use the services

If you only submit a query, you need to use the services? Let us look at the definition of services: Quote Transactions are described in terms of ACID properties, which are as follows: n Atomic: all changes to the database made in a transaction are rolled

Java in the collection, intersection, union, difference operation

How to find two identical elements in the collection of the number of . The number of different elements, etc. , You can use the collection of and, to , With a set operation, the poor :apache.commons.collections.CollectionUtils This class provides support
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