The 'static' keyword is used to declare a variable or method to be part of the class itself rather than an instance of it. For example, take the standard Java class 'Math'. To use its methods you can simply specify the name of the class and the method yo...
error("Variable name: " + decl.getVariableName()); err.error("Line number of reference: " + var.getLocation().getLineNumber() + " in " + var.getLocation().getSystemId()); err.error("Line number of declaration: " + decl.getLocation().getLineNumber() + " in " + decl.getLocation()...
因为name 为字符串类型,MySql 会做隐式的类型转换,做了类型的转换,所以不会去走索引; 10.少用or或in,用它查询时,mysql不一定使用索引,mysql内部优化器会根据检索比例、表大小等多个因素整体评估是否使用索引,详见范围查询优化 EXPLAIN SELECT * FROM employees WHERE name = 'LiLei' or name = 'HanMeimei'; ...
| Variable_name | Value | +---+---+ | Qcache_queries_in_cache | 8 | | Qcache_inserts | 545875 | | Qcache_hits | 83951 | | Qcache_lowmem_prunes | 0 | | Qcache_not_cached | 2343256 | | Qcache_free_memory | 33508248 | | Qcache_free_blocks | 1 | | Qcache_total_blocks | ...
If it would have been a class level static variable then it would have been visible in method2(). So your variable x here is a local variable to the static method method1() and hence it is not accessible in method2() Thanks and Regards, Suhas http://www.xplore-java.blogspot.com/...
For example, when the SQL statement contains bind variables the plan shown from using EXPLAIN PLAN ignores the bind variable values while the plan shown in V$SQL_PLAN takes the bind variable values into account in the plan generation process. It is easy to display an execution plan using the...
| Variable_name | Value | +---+---+ | log_slow_admin_statements | OFF | | log_slow_slave_statements | OFF | | slow_launch_time | 2 | | slow_query_log | OFF | | slow_query_log_file | F:\mysql-5.7.25\data\DESKTOP-7TLR5VO-slow....
So what we see here, variable is assigned a new value which was a boolean true (1 in numeric form). In the end, we print , who's value is now 1, multiplied by , which gives us 1 * 1. Next, print a space followed by value of which was not altered (still 1). That's...
QSM-02056 correlated variable and outer join in materialized view Cause: The capability in question is not supported when the materialized view uses a correlated variable and an outer join. Action: Re-phrase the query to avoid the use of correlated variables or outer joins. QSM-02057 ROWNUM ...
There is also a ThreadLocal object in InternalThreadLocalMap, called slowThreadLocalMap, which is used when fastThreadLocalMap does not take effect. Next, let's take a look at why this ThreadLocalMap is fast: public static InternalThreadLocalMap get() { ...