SQL ORA-01408: 此类列列表已编入索引
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ORA-01408: such column list already indexed
提问by My-Name-Is
Oracle SQL-Developer generates DDL statements of already exising database tables (items). It's quite strange that the generated DDL statements can't be applied within a new database instance. Here's a simplified example of the DDL
Oracle SQL-Developer 生成现有数据库表（项）的 DDL 语句。很奇怪，生成的 DDL 语句不能应用于新的数据库实例。这是 DDL 的简化示例
CREATE TABLE AB
(
"A" NUMBER(*,0),
"B" NUMBER(*,0),
"C" VARCHAR2(255 BYTE),
CONSTRAINT "CHK_AB_A_NN" CHECK (A IS NOT NULL) ENABLE,
CONSTRAINT "CHK_AB_B_NN" CHECK (B IS NOT NULL) ENABLE,
CONSTRAINT "PK_AB" PRIMARY KEY ("A", "B")
);
CREATE INDEX "IDX_AB_A" ON "AB"("A");
CREATE INDEX "IDX_AB_B" ON "AB"("B");
CREATE UNIQUE INDEX "PK_AB" ON "AB"("A", "B");
If I execute those statements within a new oracle instance, I get the error:
如果我在新的 oracle 实例中执行这些语句，则会收到错误消息：
SQL-Fehler: ORA-01408: Diese Spaltenliste hat bereits einen Index
1. 00000 - "such column list already indexed"
SQL-Fehler: ORA-01408: Diese Spaltenliste hat bereits einen Index
1. 00000 - "such column list already indexed"
What's the reason for this error?
这个错误的原因是什么？
回答by Alen Oblak
The part:
那个部分：
CONSTRAINT "PK_AB" PRIMARY KEY ("A", "B")
is generating an index. Primary key constraint cannot exists without an index. However, the part:
正在生成索引。没有索引就不能存在主键约束。但是，该部分：
CREATE UNIQUE INDEX "PK_AB" ON "AB"("A", "B");
is generating yet another index with the same columns. This is the reason for the error. Quite strange though, that the Oracle tool is generating a wrong script :) Maybe it's a bug.
正在生成另一个具有相同列的索引。这就是错误的原因。不过很奇怪，Oracle 工具生成了错误的脚本 :) 也许这是一个错误。
回答by tvm
Your primary key constraint in the CREATE TABLE statement automatically creates unique index on ("A","B"), since it's PRIMARY KEY. Error is then raised, since you try to re-create already existing UNIQUE INDEX on same columns.
CREATE TABLE 语句中的主键约束会自动在 ("A","B") 上创建唯一索引，因为它是 PRIMARY KEY。然后引发错误，因为您尝试在相同的列上重新创建现有的 UNIQUE INDEX。
UPDATE: I've tested it with Oracle SQL Developer 3.2.20.09 and the above mentioned problem is not present. Are you possibly using older version ?
更新：我已经使用 Oracle SQL Developer 3.2.20.09 对其进行了测试，并且不存在上述问题。您可能使用旧版本吗？
