Database and SQL

mysql_fetch_array returns a row as an array with both numeric indices (0, 1, 2...) and associative keys (column names). mysql_fetch_row returns only a numeric array, while mysql_fetch_object returns an object. The function name 'array' specifically indicates it can return both types.

Minimal super key is called as candidate key.

A foreign key means that values in one table must also appear in another table.

Part of primary key cannot contain a null value.

From candidate keys a database designer chooses a primary key.

This is not a valid predicate in SQL

The query will find any string that begins with the letter 'S'

COMMIT transaction makes all data modifications performed since the start from the transaction from a permanent part of the database, it frees the resources held by the transaction.

It will find any string that contains the letter 'A' followed by any single character followed by the letter 'E'. And in between the name there is a ALE form.

IN will find any value existing in a set of candidates.

This constraint is used in Oracle to prevent the duplication of values within the rows of a specified column or a set of columns in a table.

This component of select command is used to summarize the data of the table.

This attribute of cursor command in Oracle is used to return no more records from the cursor if it fails.

This method is used in java to execute an SQL statement that may return multiple results.

Create, Revoke, Grant and Drop commands are parts of data definition language in Oracle.