java ejb開發(fā) 程序4、語(yǔ)句alter table people add(phone_number varchar2(10)) 的作用是 A 修改表結(jié)構(gòu) B 為people表添加約束，約束名稱是phone_number C 向people表中添加一列，名稱是phone_number，數(shù)據(jù)類型是varchar2，長(zhǎng)度是10 D 上述答案均不正確 5、（ ）BLOB和CLOB的區(qū)別在于 A CLOB只能存放字符類型的數(shù)據(jù)，而BLOB沒有任何限制 B BLOB只能存放字符類型的數(shù)據(jù)，而CLOB沒有任何限制 C CLOB只能存放小于4000字節(jié)的數(shù)據(jù)，而BLOB可以存放大于4000字節(jié)的數(shù)據(jù) D BLOB只能存放小于4000字節(jié)的數(shù)據(jù)，而CLOB可以存放大于4000字節(jié)的數(shù)據(jù) 6、存儲(chǔ)過程從本質(zhì)上來講就是 A 匿名的PL/SQL程序塊，它可以被賦予參數(shù) B 命名的PL/SQL程序塊，它可以被賦予參數(shù) C 命名的PL/SQL程序塊，不能被賦予參數(shù) D 匿名的PL/SQL程序塊，不能被賦予參數(shù) 7、（ ）下列關(guān)于日期數(shù)據(jù)類型，哪一個(gè)語(yǔ)句是正確的寫法 A insert into test values( 9999-12-03 ) B insert into test values( 1999-03-02 ) C insert into test values(to_char(1999-06-03, yyyy/dd/mm )) D insert into test
This project attempts to implement a Database using B+Tree. The project has developed a DATABASE SYSTEM with lesser memory consumption. Its API includes simple SQL Statements and the output is displayed on the screen. Certain applications for which several features of existing databases like concurrency control, transaction management, security features are not enabled. B+Trees can be used as an index for factor access to the data. Help facility is provided to know the syntax of SQL Statements.
Let the following relational tables be given: R = (A, B, C) and S = (D, E, F) where A, B, C, D, E, and F are the attributes (columns). Write the SQL statements that will express each of the queries given below:
