Updating tables with foreign key constraints

03-Nov-2019 23:27 by 8 Comments

Updating tables with foreign key constraints

A foreign key with cascade delete means that if a record in the parent table is deleted, then the corresponding records in the child table will automatically be deleted. A foreign key with cascade delete can be created using either a CREATE TABLE statement or an ALTER TABLE statement.

The time-tested solution to a flat file is a relational database.CONSTRAINT fk_name FOREIGN KEY (child_col1, child_col2, ...child_col_n) REFERENCES parent_table (parent_col1, parent_col2, ... parent_col_n) ON DELETE CASCADE [ ON UPDATE ] ); The columns that you wish to create in the table. The column should either be defined as NULL or NOT NULL and if this value is left blank, the database assumes NULL as the default.If the column name is "LAST_NAME" and the column is defined as CHAR(20) it is be stored as Oracle starts adding rows from the end of the block towards the block header.In this way, the block header can grow if required.Clients MUST send all JSON API data in request documents with the header .

JSON API documents are defined in Java Script Object Notation (JSON) [RFC7159].

Although the same media type is used for both request and response documents, certain aspects are only applicable to one or the other. Unless otherwise noted, objects defined by this specification MUST NOT contain any additional members.

Client and server implementations MUST ignore members not recognized by this specification.

This section describes guidelines to follow when managing tables.

Following these guidelines can make the management of your tables easier and can improve performance when creating the table, as well as when loading, updating, and querying the table data.

After you create a table, you insert rows of data using SQL statements or using an Oracle bulk load utility.