How to query data type in oracle

In Oracle, you can use the "select ... From all_tab_columns where table_name=upper('table name') AND owner=upper('database login user name');" statement to query the data type of the database table .

The operating environment of this tutorial: Windows 10 system, Oracle 11g version, Dell G3 computer.

How to query data type in oracle

The syntax of oracle query data type is as follows:

select column_name,data_type,DATA_LENGTH From all_tab_columns where table_name=upper('表名') AND owner=upper('数据库登录用户名');

The example is as follows:

select column_name,data_type,DATA_LENGTH From all_tab_columns
where table_name=upper('t_department') AND owner=upper('scott')

Expand knowledge:

1. View the field name and data type

select * from cols WHERE TABLE_name=upper('表名'); (user_tab_columns缩写cols)

2. View the data type of the specified column

select DATA_TYPE from User_Tab_Columns t where t.column_name=upper('列名') and t.table_name =upper(trim('表名'));

3. View all columns

select * from user_tab_columns where table_name = upper(‘表名’);

4. View certain columns

select column_name,data_type,data_length,DATA_PRECISION ,DATA_SCALE from all_tab_columns where table_name=upper('表名');

5. You can view all constraints through user_constraints

select * from user_constraints where table_name = upper('表名');

6. View primary key constraints:

select * from user_constraints where constraint_type='P'
and TABLE_name=upper('表名');

Recommended tutorial: "Oracle Video tutorial》

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