Start Updating one column table another column

Updating one column table another column

The database uses the object identifier to construct When a table (relational table) is defined with a column of an object type, the database adds hidden columns to the table for the leaf-level attributes of the object type.

This blog post illustrates how to update more than one column in a table with values from columns in another table and explains how to do it in the three RDBMS that we support.

Table Structures and values: Table A has four columns: a, b, c, d (a is the primary key column) Table B has five columns: a1, b1, c1, d1, e1 (a1 and b1 together constitute the primary key for this table) The foreign key relationship between the two tables is based on A.a = B.a1 The data in these 2 tables is as follows: I. Table B a1 b1 c1 d1 e1 1 x1 y1 z1 40 2 a1 b1 c1 50 The requirement is to write a SQL to update columns b, c and d in Table A from the columns b1, c1 and d1 from Table B where-ever the join condition satisfies and e1 40) / Results after the update: a b c d ———————————— 1 x y z 2 a1 b1 c1 3 t x z SQL Server: UPDATE TABLEA SET b = TABLEB.b1, c = TABLEB.c1, d = TABLEB.d1 FROM TABLEA, TABLEB WHERE TABLEA.a = TABLEB.a1 AND TABLEB.e1 40 GO Note: This is an extension in SQL Server i.e.

These retrofit the tables to store data of the new type.

If, for some reason, the columns cannot be added, creation of the subtype is rolled back.

Ultimately, each branch ends at an attribute that is a built-in type; such as is also stored in a column, unless it is too large.

Oracle database stores leaf-level attributes of nested table types in separate tables associated with the object table.

Typically, a typeid ( The rows of a nested table are stored in a separate storage table.

Each nested table column has a single associated storage table.

The type-discriminant column contains typeids that identify the most specific type of every object instance stored in the substitutable column.

The system uses this information to evaluate queries that filter by type using the function.

For example, the following statement creates a bitmap index on the type-discriminant column underlying the substitutable -- Requires Ex.