云数据库 TaurusDB-字段压缩:语法

时间：2025-02-12 15:04:25

云数据库 TaurusDB

语法

扩展column_definition定义，支持在CREATE TABLE/ALTER TABLE ADD/ALTER TABLE CHANGE/ALTER TABLE MODIFY场景定义列属性时使用压缩特性。

create_definition: {    col_name column_definition  | {INDEX | KEY} [index_name] [index_type] (key_part,...)      [index_option] ...  | {FULLTEXT | SPATIAL} [INDEX | KEY] [index_name] (key_part,...)      [index_option] ...  | [CONSTRAINT [symbol]] PRIMARY KEY      [index_type] (key_part,...)      [index_option] ...  | [CONSTRAINT [symbol]] UNIQUE [INDEX | KEY]      [index_name] [index_type] (key_part,...)      [index_option] ...  | [CONSTRAINT [symbol]] FOREIGN KEY      [index_name] (col_name,...)      reference_definition  | check_constraint_definition}alter_option: {    table_options  | ADD [COLUMN] col_name column_definition        [FIRST | AFTER col_name]  | ADD [COLUMN] (col_name column_definition,...)  | CHANGE [COLUMN] old_col_name new_col_name column_definition        [FIRST | AFTER col_name]  | MODIFY [COLUMN] col_name column_definition        [FIRST | AFTER col_name]  ...

其中column_definition为：

column_definition: {    data_type [NOT NULL | NULL] [DEFAULT {literal | (expr)} ]      [VISIBLE | INVISIBLE]      [AUTO_INCREMENT] [UNIQUE [KEY]] [[PRIMARY] KEY]      [COMMENT 'string']      [COLLATE collation_name]      [COLUMN_FORMAT {FIXED | DYNAMIC | DEFAULT}]      [COLUMN_FORMAT {FIXED|DYNAMIC|DEFAULT}|COMPRESSED[={ZLIB|ZSTD}**]]      [ENGINE_ATTRIBUTE [=] 'string']      [SECONDARY_ENGINE_ATTRIBUTE [=] 'string']      [STORAGE {DISK | MEMORY}]      [reference_definition]      [check_constraint_definition]  | data_type      [COLLATE collation_name]      [GENERATED ALWAYS] AS (expr)      [VIRTUAL | STORED] [NOT NULL | NULL]      [VISIBLE | INVISIBLE]      [UNIQUE [KEY]] [[PRIMARY] KEY]      [COMMENT 'string']      [reference_definition]      [check_constraint_definition]}

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