In SQL Server CREATE INDEX command creates a relational index on a table or view. Also called a rowstore index because it is either a clustered or nonclustered btree index. You can create a rowstore index before there is data in the table. Use a rowstore index to improve query performance,...
key_part: {col_name[(length)]|(expr)}[ASC | DESC]index_type: USING {BTREE|HASH} index_option: KEY_BLOCK_SIZE[=]value|index_type|WITHPARSER parser_name|COMMENT'string'|{VISIBLE|INVISIBLE} reference_definition:REFERENCEStbl_name (key_part,...)[MATCH FULL | MATCH PARTIAL | MATCH SIMPLE]...
1. 在test_1表的xh字段上创建唯一索引 代码语言:javascript 代码运行次数:0 运行 AI代码解释 testdb=>create unique index"rule_test_1"on"public"."test_1"usingbtree("xh");ERROR:Cannot create index whose evaluation cannot be enforced to remote nodestestdb=> 2. 查看test_1的分布列,test_1的分布...
insert into rw_split select generate_series(1,50000), md5(random()::text)::text; create index rw_split_col_hash on rw_split using hash(col); explain select * from rw_split where col =2; ---btree 索引 drop index rw_split_col_hash; create index rw_split_col_btree on rw_split usi...
CREATETABLEitem()locality='F,R{all_server}@hz1, F,R{all_server}@hz2, F,R{all_server}@hz3'DUPLICATE_SCOPE="cluster" 创建带索引的表。 createtablet1(c1intprimarykey,c2int,c3int,indexi1(c2)); 创建Hash 分区,分区数为 8 的表。
● index_type 有些存储引擎允许在创建索引时指定索引类型。索引类型说明符的语法是 USING type_name。 示例: AI检测代码解析 1. CREATE TABLE lookup 2. (id INT, INDEX USING BTREE (id)) 3. ENGINE = MEMORY; 1. 2. 3. USING 的首选使用位置是在索引列列表之后。它可以在列的列表之前给出,但是不推...
以PostgreSQL 为例,假如我们在 pg 中随机插入了一些数据,它们完全是无序的,sql 如下: CREATE TABLE users ( id int, name varchar(255...下图是 PostgreSQL 中的一个例子: Covering Index covering index,即覆盖索引,意思是如果一条查询能够在索引当中获取到所需要的数据,就不用去获取整个 tuple...Index Includ...
CREATE INDEX CREATE LANGUAGE CREATE MASKING POLICY CREATE MATERIALIZED VIEW CREATE MODEL CREATE NODE CREATE NODE GROUP CREATE PACKAGE CREATE PROCEDURE CREATE RESOURCE LABEL CREATE RESOURCE POOL CREATE ROLE CREATE ROW LEVEL SECURITY POLICY CREATE SCHEMA ...
MySQL支持多种方法在单个或多个列上创建索引:在创建表的定义语句CREATE TABLE中指定索引列,使用ALTER TABLE语句在存在的表上创建索引,或者使用CREATE INDEX语句在已存在的表上添加索引。 1.创建表的时候创建索引 使用CREATETABLE创建表时,除了可以定义列的数据类型外,还可以定义主键约束、外键约束或者唯一性约束,而不...
btree: B-tree indexes store key values of data in a B+ tree structure. This structure helps users to quickly search for indexes. B-tree is applicable to comparison query and range query. ubtree: Multi-version B-tree index used only for Ustore tables. The index page contains transaction ...