Oracle几个常用的伪列(Pseudo-column)使用 Oracle的Pseudo-column,常被翻译成伪列,也有人翻译成虚拟字段。常常在我们的数据操作中带来一些意想不到的效果. 常用到的主要有 sysdate, systimestamp,RowNum ,RowID, CURRVAL, NEXTVAL,UID, USER,Level,ORA_ROWSCN 1.SYSDATE, SYSTIMESTAMP, SYSDATE 返回当前的系统时间。
SQL recognizes the pseudocolumns in Table 3-2, which return specific data items: Table 3-2 Pseudocolumns and Internal Datatypes Pseudocolumn Internal Datatype CURRVAL NUMBER LEVEL NUMBER NEXTVAL NUMBER ROWID ROWID ROWLABEL MLSLABEL ROWNUM NUMBER Pseudocolumns are not actual columns in a table. Howe...
PseudoColumnUsageを使用するパッケージ パッケージ 説明 java.sql Javaプログラミング言語を使用して、データ・ソース(通常はリレーショナル・データベース)に格納されているデータにアクセスして処理するためのAPIを提供します。 java.sqlでのPseudoColumnUsageの使用 ...
Changes in This Release for Oracle Database SQL Language Reference 1 Introduction to Oracle SQL 2 Basic Elements of Oracle SQL 3 Pseudocolumns Hierarchical Query Pseudocolumns Sequence Pseudocolumns Version Query Pseudocolumns COLUMN_VALUE Pseudocolumn OBJECT_ID Pseudocolumn OBJECT_VALUE Pseudocolumn ORA...
伪列(pseudocolumn)ROWNUM 中包含有当前的行号。很多人在第一次试图返回表中中间某段记录子集时,都会发现下面这种 … database.51cto.com|基于270个网页 2. 僞列 ROWID ROWID是一种特殊的列类型,称之为僞列(pseudocolumn)。ROWID僞列在SQL SELECT语句中可以像普通列那样 … ...
Oracle contains a pseudocolumn called rowid which returns a unique id for every row in a table. In procedual sql, this is often more convenient than a compound primary key when looping through a cursor and attempting to update the current record. Does DB2 have anything equivalent? Sort by ...
LEVEL pseudocolumn Supported Sequence Pseudocolumns Table 2Sequences No. Oracle GaussDB Difference 1 currval Supported, with differences It is implemented as a function in GaussDB. 2 nextval Supported, with differences It is implemented as a function in GaussDB. ...
Java documentation forjava.sql.DatabaseMetaData.versionColumnPseudo. Portions of this page are modifications based on work created and shared by theAndroid Open Source Projectand used according to terms described in theCreative Commons 2.5 Attribution License. ...
java.sql.PseudoColumnUsage 实现的所有接口 Serializable, Comparable<PseudoColumnUsage> public enum PseudoColumnUsage extends Enum<PseudoColumnUsage> 伪/隐藏列使用的枚举。 从以下版本开始: 1.7 另请参见: DatabaseMetaData.getPseudoColumns(java.lang.String, java.lang.String, java.lang.String, ...
When this procedure is compiled, PL/SQL looks up the structure of the company_employees table and defines a record that has a field for each column in the table, with the same name and data type. By using %ROWTYPE to declare the record, I also tell Oracle Database that this procedure...