ddl

问题 I am working with MS-Access and JSP. I want to know that how can we create table with autonumber field and with primary key. query="Create Table Registration_A (Reg_No PRIMARY KEY AUTOINCREMENT, FName varchar(2))"; But its giving syntax error. What's the correct syntax? 回答1: CREATE TABLE Registration_A ( Reg_No AUTOINCREMENT, FName VARCHAR(2), CONSTRAINT RegA_PK PRIMARY KEY(Reg_No)) 回答2: You can use the COUNTER keyword to create an AutoNumber field using DDL. I just tested this in a Java

问题 I have a pair of columns that were unfortunately defined incorrectly as TIMESTAMP(6) instead of TIMESTAMP(6) WITH TIME ZONE . I would like to migrate those columns from the old, wrong datatype to the new, correct one. On top of that, the values appear to have been captured in E(S|D)T and I need the value in UTC. So far, the best I've got is: alter table OOPSIE_TABLE add ( NEW_COLUMN_A timestamp(6) with time zone, NEW_COLUMN_B timestamp(6) with time zone ); update OOPSIE_TABLE set NEW_COLUMN_A

问题 DDL commands follow: CREATE TABLE — creates a table with the column names the user provides. DROP TABLE — deletes all rows and removes the table definition from the database. ALTER TABLE — adds or removes a column from a table. I need few examples if there is a possibility of using these Commands in PostgreSQL and Java? public boolean create(Employee employee) { try { callableStatement = openConnection().prepareCall("{call insert_employee(?,?,?)}"); callableStatement.setInt(1, employee.getEid

问题 I make DDL changes using SQL Developer's GUI. Problem is, I need to apply those same changes to the test environment. I'm wondering how others handle this issue. Currently I'm having to manually write ALTER statements to bring the test environment into alignment with the development environment, but this is prone to error (doing the same thing twice). In cases where there's no important data in the test environment I usually just blow everything away, export the DDL scripts from dev and run

问题 Trying to create a table with a foreign key. I keep getting ORA-00904 error. What am I doing wrong. Is it because table of the foreign key is not yet created ? CREATE TABLE ingredients( ingredient_id number(2,0), ingredient VARCHAR2(55) NOT NULL, quantity_required VARCHAR2(15) NOT NULL, optional_ingredient VARCHAR2(30) NOT NULL, CONSTRAINT pk_ingr_id PRIMARY KEY(ingredient_id), CONSTRAINT fk_ingredient_list FOREIGN KEY(id) REFERENCES ingredient_list(id) ); 回答1: Take a look at the following

问题 The table structure remains same after truncate statement and only records get deleted (with auto commit). Then what is the reason that truncate is a DDL statement ? 回答1: I'd add here some explanation: By default, when truncating a table , you are not just removing rows, you are implicitly telling Oracle Database to also perform the following tasks: Deallocates all space used by the removed rows except that specified by the MINEXTENTS storage parameter Sets the NEXT storage parameter to the

问题 Table: customers ID NAME DATATYPE NUMBER VARCHAR2(100) CLOB I want to change the DATA column from CLOB to `VARCHAR2(1000) I have try ALTER TABLE customers MODIFY DATA VARCHAR2 (1000) also ALTER TABLE customers MODIFY (DATA VARCHAR2 (1000)) also alter table customers modify (data VARCHAR2(4000)) those normally works if the datatype is not a clob but I am getting a ORA-22859 because I am using oracle toad/apex. 回答1: You may try this: Add a new column as varchar2 alter table my_table add (new

问题 I have granted the user in my connection to create tables, triggers, procedures, and sequence using sql+ ( grant create table to <my_user> ); however, that still does not allow me to create a table in that schema showing the error message: java.sql.sqlsyntaxerrorexception ora-01031 insufficient privileges select * from session_privs; shows: PRIVILEGE UNLIMITED TABLESPACE CREATE TABLE CREATE CLUSTER CREATE SEQUENCE CREATE PROCEDURE CREATE TRIGGER CREATE TYPE CREATE OPERATOR CREATE INDEXTYPE

问题 I look for a way how I can create a ddl for my jpa annotated entities. I prefer a pure java way for this. If possible it would be nice to have generate the drop statements too. 回答1: Export data from a database as sql Use the liquibase opensource project LiquiBase is an open source (LGPL), database-independent library for tracking, managing and applying database changes. It is built on a simple premise: All database changes (structure and data) are stored in an XML-based descriptive manner and

问题 My database background is with Oracle, so I was surprised to discover that Postgres includes schema changes in transactions - if you begin one, create a table and then rollback, the table goes away. It works for adding and removing columns as well. Obviously this is very nice. We're about to make some changes to the way we deploy schema deltas that rely on this feature. Before we do, I'd like to find out how far the transactional guarantee extends, but I can't find any information on it in