PUCRS FACIN - Laboratório de Banco de Dados Prof. Duncan Aula de 03/04/2006. Sintaxe ANSI para comandos INSERT, UPDATE e DELETE

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1 Sintaxe ANSI para comandos INSERT, UPDATE e DELETE

2 Sintaxe Oracle para comandos de atualização: INSERT Statement The INSERT statement adds new rows of data to a specified database table. For a full description of the INSERT statement, see Oracle9i SQL Reference. Syntax Keyword and Parameter Description alias This is another (usually short) name for the referenced table or view. column_name[, column_name]... This identifies a list of columns in a database table or view. Column names need not appear in the order in which they were defined by the CREATE TABLE or CREATE VIEW statement. However, no column name can appear more than once in the list. If the list does not include all the columns in a table, the missing columns are set to NULL or to a default value specified in the CREATE TABLE statement. returning_clause This clause lets you return values from inserted rows, thereby eliminating the need to SELECT the rows afterward. You can retrieve the column values into variables and/or host variables, or into collections and/or host arrays. However, you cannot use the RETURNING clause for remote or parallel inserts. For the syntax of returning_clause, see "DELETE Statement". sql_expression This is any expression valid in SQL. For more information, see Oracle9i SQL Reference. subquery This is a SELECT statement that provides a set of rows for processing. Its syntax is like that of select_into_statement without the INTO clause. See "SELECT INTO Statement". subquery3 This is a SELECT statement that returns a value or set of values. As many rows are added to the table as are returned by the subquery. It must return a value for every column in the column list or for every column in the table if there is no column list. table_reference This identifies a table or view that must be accessible when you execute the INSERT statement, and for which you must have INSERT privileges. For the syntax of table_reference, see "DELETE Statement". TABLE (subquery2) The operand of TABLE is a SELECT statement that returns a single column value, which must be a nested table. Operator TABLE informs Oracle that the value is a collection, not a scalar value.

3 VALUES (...) This clause assigns the values of expressions to corresponding columns in the column list. If there is no column list, the first value is inserted into the first column defined by the CREATE TABLE statement, the second value is inserted into the second column, and so on. There must be only one value for each column in the column list. Also, the datatypes of the values being inserted must be compatible with the datatypes of corresponding columns in the column list. Usage Notes Character and date literals in the VALUES list must be enclosed by single quotes ('). Numeric literals are not enclosed by quotes. The implicit cursor SQL and the cursor attributes %NOTFOUND, %FOUND, %ROWCOUNT, and %ISOPEN let you access useful information about the execution of an INSERT statement. Examples The following examples show various forms of INSERT statement: INSERT INTO bonus SELECT ename, job, sal, comm FROM emp WHERE comm > sal * 0.25;... INSERT INTO emp (empno, ename, job, sal, comm, deptno) VALUES (4160, 'STURDEVIN', 'SECURITY GUARD', 2045, NULL, 30);... INSERT INTO dept VALUES (my_deptno, UPPER(my_dname), 'CHICAGO'); UPDATE Statement The UPDATE statement changes the values of specified columns in one or more rows in a table or view. For a full description of the UPDATE statement, see Oracle9i SQL Reference. Syntax Keyword and Parameter Description alias This is another (usually short) name for the referenced table or view and is typically used in the WHERE clause. column_name This is the name of the column (or one of the columns) to be updated. It must be the name of a column in the referenced table or view. A column name cannot be repeated in the column_name list. Column names need not appear in the UPDATE statement in the same order that they appear in the table or view. returning_clause This clause lets you return values from updated rows, thereby eliminating the need to SELECT the rows afterward. You can retrieve the column values into variables and/or host variables, or into collections and/or host arrays. However, you

4 cannot use the RETURNING clause for remote or parallel updates. For the syntax of returning_clause, see "DELETE Statement". SET column_name = sql_expression This clause assigns the value of sql_expression to the column identified by column_name. If sql_expression contains references to columns in the table being updated, the references are resolved in the context of the current row. The old column values are used on the right side of the equal sign. In the following example, you increase every employee's salary by 10%. The original value of the sal column is multiplied by 1.10, then the result is assigned to the sal column overwriting the original value. UPDATE emp SET sal = sal * 1.10; SET column_name = (subquery3) This clause assigns the value retrieved from the database by subquery3 to the column identified by column_name. The subquery must return exactly one row and one column. SET (column_name, column_name,...) = (subquery4) This clause assigns the values retrieved from the database by subquery4 to the columns in the column_name list. The subquery must return exactly one row that includes all the columns listed. The column values returned by the subquery are assigned to the columns in the column list in order. The first value is assigned to the first column in the list, the second value is assigned to the second column in the list, and so on. In the following correlated query, the column item_id is assigned the value stored in item_num, and the column price is assigned the value stored in item_price: UPDATE inventory inv -- alias SET (item_id, price) = (SELECT item_num, item_price FROM item_table WHERE item_name = inv.item_name); sql_expression This is any valid SQL expression. For more information, see Oracle9i SQL Reference. subquery This is a SELECT statement that provides a set of rows for processing. Its syntax is like that of select_into_statement without the INTO clause. See "SELECT INTO Statement". table_reference This identifies a table or view that must be accessible when you execute the UPDATE statement, and for which you must have UPDATE privileges. For the syntax of table_reference, see "DELETE Statement". TABLE (subquery2) The operand of TABLE is a SELECT statement that returns a single column value, which must be a nested table or a varray. Operator TABLE informs Oracle that the value is a collection, not a scalar value. WHERE CURRENT OF cursor_name This clause refers to the latest row processed by the FETCH statement associated with the cursor identified by cursor_name. The cursor must be FOR UPDATE and must be open and positioned on a row. If the cursor is not open, the CURRENT OF clause causes an error. If the cursor is open, but no rows have been fetched or the last fetch returned no rows, PL/SQL raises the predefined exception NO_DATA_FOUND. WHERE search_condition This clause chooses which rows to update in the database table. Only rows that meet the search condition are updated. If you omit the search condition, all rows in the table are updated. Usage Notes You can use the UPDATE WHERE CURRENT OF statement after a fetch from an open cursor (this includes implicit fetches executed in a cursor FOR loop), provided the associated query is FOR UPDATE. This statement updates the current row, that is, the one just fetched. The implicit cursor SQL and the cursor attributes %NOTFOUND, %FOUND, %ROWCOUNT, and %ISOPEN let you access useful information about the execution of an UPDATE statement. Examples In the following example, a 10% raise is given to analysts in department 20: UPDATE emp SET sal = sal * 1.10 WHERE job = 'ANALYST' AND DEPTNO = 20;

5 In the next example, an employee named Ford is promoted to the position of Analyst and her salary is raised by 15%: UPDATE emp SET job = 'ANALYST', sal = sal * 1.15 WHERE ename = 'FORD'; In the final example, values returned from an updated row are stored in variables: UPDATE emp SET sal = sal WHERE ename = 'MILLER' RETURNING sal, ename INTO my_sal, my_ename; DELETE Statement The DELETE statement removes entire rows of data from a specified table or view. For a full description of the DELETE statement, see Oracle9i SQL Reference. Syntax Keyword and Parameter Description alias This is another (usually short) name for the referenced table or view and is typically used in the WHERE clause. BULK COLLECT This clause instructs the SQL engine to bulk-bind output collections before returning them to the PL/SQL engine. The SQL engine bulk-binds all collections referenced in the RETURNING INTO list. The corresponding columns must store scalar (not composite) values. For more information, see "Reducing Loop Overhead for Collections with Bulk Binds". returning_clause This clause lets you return values from the deleted rows, thereby eliminating the need to SELECT the rows beforehand. You can retrieve the column values into variables and/or host variables, or into collections and/or host arrays. However, you cannot use the RETURNING clause for remote or parallel deletes. subquery This is a SELECT statement that provides a set of rows for processing. Its syntax is like that of select_into_statement without the INTO clause. See "SELECT INTO Statement".

6 table_reference This specifies a table or view, which must be accessible when you execute the DELETE statement, and for which you must have DELETE privileges. TABLE (subquery2) The operand of TABLE is a SELECT statement that returns a single column value, which must be a nested table. Operator TABLE informs Oracle that the value is a collection, not a scalar value. WHERE CURRENT OF cursor_name This clause refers to the latest row processed by the FETCH statement associated with the cursor identified by cursor_name. The cursor must be FOR UPDATE and must be open and positioned on a row. If the cursor is not open, the CURRENT OF clause causes an error. If the cursor is open, but no rows have been fetched or the last fetch returned no rows, PL/SQL raises the predefined exception NO_DATA_FOUND. WHERE search_condition This clause conditionally chooses rows to be deleted from the referenced table or view. Only rows that meet the search condition are deleted. If you omit the WHERE clause, all rows in the table or view are deleted. Usage Notes You can use the DELETE WHERE CURRENT OF statement after a fetch from an open cursor (this includes implicit fetches executed in a cursor FOR loop), provided the associated query is FOR UPDATE. This statement deletes the current row; that is, the one just fetched. The implicit cursor SQL and the cursor attributes %NOTFOUND, %FOUND, and %ROWCOUNT let you access useful information about the execution of a DELETE statement. Examples The following statement deletes from the bonus table all employees whose sales were below quota: DELETE FROM bonus WHERE sales_amt < quota; The following statement returns two column values from a deleted row into local variables: DECLARE my_empno emp.empno%type; my_ename emp.ename%type; my_job emp.job%type; BEGIN... DELETE FROM emp WHERE empno = my_empno RETURNING ename, job INTO my_ename, my_job; END; You can combine the BULK COLLECT clause with a FORALL statement, in which case, the SQL engine bulk-binds column values incrementally. In the following example, if collection depts has 3 elements, each of which causes 5 rows to be deleted, then collection enums has 15 elements when the statement completes: FORALL j IN depts.first..depts.last DELETE FROM emp WHERE deptno = depts(j) RETURNING empno BULK COLLECT INTO enums; The column values returned by each execution are added to the values returned previously.