字段系统表描述

描述

包含有关数据库中每个持久性表中的每个字段的信息。

领域

字段名称 类型 描述

场地

细绳

字段名称,这也是列的名称。

Tablename.

细绳

此字段/列的表名。

架构

细绳

该字段/列表的模式名称。

domainname.

细绳

If this column is defined as a SQL DOMAIN, this is the DOMAIN name. Otherwise, null.

穹顶

细绳

If this column is defined as a SQL DOMAIN, this is the name of the schema for the DOMAIN. Otherwise, null.

融合序列

细绳

If this column is a 细绳 type and a collation was specified, this is the name of the collation. Otherwise, null.

现场门

整数

This is the position of the field specifying the order in which the field was given in the original 创建表 command. IDs will continue to be incremented by one in ascending order for any columns added by ALTER TABLE, despite any columns dropped by 改变表.

领域

整数

This is the same as 现场门.

数据类型

整数

Integer from ID in SYSTEM.DATATYPES for this column’s data type.

长度

整数

Length associated with the data type for this column. This is the precision assigned to a CHAR or BINARY type or the size in bytes of the type.

规模

整数

如果列被定义为固定精度数字类型,则这是比例。否则,0。

精确

整数

If the column is defined as a fixed precision numeric, CHAR or BINARY type, this is the precision. Otherwise, this is the maximum precision possible for this type.

显示屏尺寸

整数

Internal field used to help the nuosql client and other clients display data.

旗帜

整数

标志指定有关此列的其他信息:

1

列是 NOT_NULL

2

保留未来使用旗帜 Searchable

4

保留未来使用旗帜 Case Insensitive

8

列是 defined as GENERATED ALWAYS AS IDENTITY, as opposed to GENERATED BY DEFAULT AS IDENTITY

默认值

细绳

创建时为列给出的默认值。

评论

细绳

没用过。

generator_sequence.

文本

包含序列的名称,如果列已被​​定义为“GENERATED…​AS IDENTITY”. See column 旗帜 for type of generation, always or by default.

枚举

文本

Contains the textual labels for fields defined as ENUM data type.

字符集

文本

没用过。

discly_type.

细绳

The actual string for the type of the column parsed from the command that created the column (创建表 or 改变表).

计算表达

细绳

用于计算字段值的表达式。 If the field is not a computed field, NULL is used.

索引

Primary Index: 场地S..PRIMARY_KEY on fields: 架构, Tablename., 场地

Secondary Index: 场地COLLATIONSEQUENCENAME on field: 融合序列

Secondary Index: 场地DOMAINNAME on fields: domainname., 穹顶