`last_update`timestampNOTNULLDEFAULTCURRENT_TIMESTAMPONUPDATECURRENT_TIMESTAMP,PRIMARYKEY(`person_id`),KEY`idx_p_a` (`postadlcode`,`age`),KEY`idx_f_l` (`first_name`,`last_name`) ) ENGINE=InnoDBDEFAULTCHARSET=utf8 关闭ICP优化,Extra信息为“Using Where” mysql>setoptimizer_switch="index_c...
Nelson, J.: Growth mechanisms to explain the primary and sec- ondary habits of snow crystals, Philos. Mag. A, 81, 2337-2373, 2001.J. Nelson, "Growth mechanisms to explain the primary and secondary habits of snow crystals," Philosophical Magazine A, vol. 81, no. 10, pp. 2337-2373,...
(1) SIMPLE:简单的select查询,查询中不包含子查询或者union (2) PRIMARY:查询中包含任何复杂的子部分,最外层查询则被标记为primary (3) SUBQUERY:在select 或 where列表中包含了子查询 (4) DERIVED:在from列表中包含的子查询被标记为derived(衍生),mysql或递归执行这些子查询,把结果放在临时表里 (5) UNION:若...
#2. mysql中的primary key,unique,联合唯一也都是索引,这些索引除了加速查找以外,还有约束的功能 2、MySQL常用的索引 普通索引INDEX:加速查找 唯一索引:-主键索引PRIMARYKEY:加速查找+约束(不为空、不能重复)-唯一索引UNIQUE:加速查找+约束(不能重复) 联合索引:-PRIMARYKEY(id,name):联合主键索引-UNIQUE(id,name)...
Briefly explain the difference between primary and secondary security. Capital Markets: This question relates to capital markets, the financial forums where savings and investments are channeled between the suppliers of capital to the users of capital. The most common capital markets are the st...
replicate-between-primary-and-secondary-clusters.md replicate-data-to-kafka.md role-based-access-control.md scale-tidb-using-tiup.md schedule-replicas-by-topology-labels.md schema-object-names.md security-compatibility-with-mysql.md shard-row-id-bits.md sql-logical-optimization.md sql-mode.md sql...
That is, thenamed index covers the selected columns, so although it is not used to determinewhich rows to retrieve, an index scan is more efficient than a data row scan. For InnoDB, a secondary index might coverthe selected columns even if the query also selects the primary key becauseInn...
The secondary databases are readable and can be used to offload read-only workloads, thus freeing up resources for transactional workloads on the primary or placing data closer to your end users. Furthermore, the secondary databases can be in the same region as the primary o...
2 The disease is categorized into idiopathic or primary, and secondary adhesive capsulitis. The pathogenesis of the idiopathic form is not very clear. Some authors suggest endocrine, immunologic, inflammatory and biochemical changes as possible causes.3 The term secondary adhesive capsulitis is used ...
aImmune deficiencies such as X-linked agammaglobulinemia, hypogammaglobulinemia (primary immune deficiencies), and acquired compromised immunity conditions (secondary immune deficiencies) featuring low antibody levels. 免疫缺乏例如X连接的丙球蛋白缺乏症,低丙球蛋白血症 (主要免疫缺乏)和获取的减弱的免疫适应 ...