Apache Derby – Alter Table Statement The ALTER TABLE statement, allows you to alter an existing table. Using this you can do the following − Add a column, add a constraint Drop a column, drop a constraint Change the row level locking of a table Let us assume we have created a table named Employees […]
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Apache Derby – Derby Indexes An index in a table is nothing but a pointer to its data. These are used to speed up the data retrieval from a table. If we use indexes, the INSERT and UPDATE statements get executed in a slower phase. Whereas SELECT and WHERE get executed with in lesser time. […]
Apache Derby – Update Data The UPDATE statement is used to update data in a table. Apache Derby provides two types of updates (syntax) namely searched update and positioned update. The searched UPDATE statement updates all the specified columns of a table. Syntax Following is the syntax of the UPDATE query − ij> UPDATE table_name […]