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GBase 8s GDCA 认证培训课前准备

GBase 8a

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物化视图报错：references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them

01-GBase 8s 事务型数据库 安装与卸载

GBase 8s

适配迁移

[GBase 8s 教程]GBase 8s 常用函数、表达式

## Pyodbc对数据类型的支持  
常用的数据类型如下：  

### 字符类型  
内置字符类型包括：char, nchar, varchar, nvarchar 和lvarchar  
CHARACTER(n) 和 CHARACTER VARYING(n)这样的别名同样支持  
参考代码：test_string_type.py  





```python
    create = """
    create table tab_string(
        col1 char(32767),
        col2 nchar(32767),
        col3 varchar(255),
        col4 nvarchar(255),
        col5 lvarchar(32739)
    )
    """
    cursor.execute(create)
    cursor.commit()

    insert = "insert into tab_string(col1, col2, col3, col4, col5) values(?,?,?,?,?)"
    cursor.execute(insert,['字符字段char类型','本地化字符字段nchar类型','可变长度字符字段varchar类型','本地化可变长度字符字段nvarchar类型','扩展可变长度字符字段lvarchar类型'])
    cursor.commit()

    select = "select * from tab_string"
    cursor.execute(select)
    data = cursor.fetchall()
    for result in data :
        print("字段1的字节长度为：{} ,值为：\"{}\"". format(len(result[0].encode('utf8')),result[0]))
        print("字段2的字节长度为：{} ,值为：\"{}\"". format(len(result[1].encode('utf8')),result[1]))
        print("字段3的字节长度为：{} ,值为：\"{}\"". format(len(result[2].encode('utf8')),result[2]))
        print("字段4的字节长度为：{} ,值为：\"{}\"". format(len(result[3].encode('utf8')),result[3]))
        print("字段5的字节长度为：{} ,值为：\"{}\"". format(len(result[4].encode('utf8')),result[4]))
```

### 数值类型  
内置的数值类型包括：  
整型：smallint, integer, int8, bigint  
自增长整型：serial, serial8, bigserail  
浮点型：smallfloat, float, decimal  
精确值型：decimal(P,S)  
货币类型：money(P,S)  
DEC(p,s)、NUMERIC(p,s)、INT和DOUBLE PRECISION这样的别名同样支持  
注意：bigint/bigserail需要指定转换  
参考代码：test_numeric_type.py  
```python
    create = """
    create table tab_numeric(
        col1 serial not null,
        col2 smallint,
        col3 int,
        col4 int8,
        col5 bigint,
        col6 smallfloat,
        col7 float,
        col8 decimal(32,20),
        col9 decimal(32),
        colx money(32,20)
    )
    """
    cursor.execute(create)

    insert = """
    insert into tab_numeric(col1, col2, col3, col4, col5, col6, col7, col8, col9, colx) values
    (0,32767,2147483647,9223372036854775807,9223372036854775807,1234567890,12345678901234567890,123456789012.123456789,12345678901234567890123456789012,123456789012.123456789)
    """
    cursor.execute(insert)
    cursor.commit()

    select = "select * from tab_numeric"
    cursor.execute(select)
    data = cursor.fetchall()
    for result in data:
        print("字段 1的类型serail         ,值为：{}" . format(result[0]))
        print("字段 2的类型samllint       ,值为：{}" . format(result[1]))
        print("字段 3的类型integer        ,值为：{}" . format(result[2]))
        print("字段 4的类型int8           ,值为：{}" . format(result[3]))
        print("字段 5的类型bigint         ,值为：{}" . format(result[4]))
        print("字段 6的类型smallfloat     ,值为：{}" . format(result[5]))
        print("字段 7的类型float          ,值为：{}" . format(result[6]))
        print("字段 8的类型decimal(32,20) ,值为：{}" . format(result[7]))
        print("字段 9的类型decimal(32)    ,值为：{}" . format(result[8]))
        print("字段10的类型money(32,20)   ,值为：{}" . format(result[9]))
```

### 日期时间型  
日期型：date  
日期时间型：datetime [first to last]  
间隔类型：interval [first to list]  
TIMESTAMP(n)这样的别名在部分版本中支持  
interval  不支持该类型（不支持读取 ODBC SQL type 109 is not yet supported） ，需要转换  
```python
    create = """
    create table tab_datetime(
        col1 serial not null,
        col2 date,
        col3 datetime year to day,
        col4 datetime year to second,
        col5 datetime year to fraction(5),
        col6 interval day to minute
    )
    """
    cursor.execute(create)
    cursor.commit()

    prepare = """
    insert into tab_datetime(col1,col2,col3,col4,col5,col6) values(0,?,?,?,?,?)
    """
    cursor.execute(prepare,['2023-03-24','2023-03-24','2023-03-24 12:34:56','2023-03-24 12:34:56.98765','-3 12:13'])
    cursor.commit()

    select = "select col1,col2,col3,col4,col5 from tab_datetime"
    cursor.execute(select)
    data = cursor.fetchall()
    for result in data:
        print("字段 1的类型serail                  ,值为：{}" . format(result[0]))
        print("字段 2的类型date                    ,值为：{}" . format(result[1]))
        print("字段 3的类型datetime Y-m-d          ,值为：{}" . format(result[2]))
        print("字段 4的类型datetime Y-m-d H:M:S    ,值为：{}" . format(result[3]))
        print("字段 5的类型datetime Y-m-d H:M:S.F5 ,值为：{}" . format(result[4]))
        # print("字段 6的类型interval d H:M          ,值为：{}" . format(result[5]))
```

### 布尔类型  
布尔类型：boolean  
取值范围：'t'/1, 'f'/0, null(None)  
参考代码：test_boolean_type.py  
```python
    create = """
    create table tab_boolean(
        col1 serial not null,
        col2 boolean
    )
    """
    cursor.execute(create)
    cursor.commit()

    prepare = """
    insert into tab_boolean(col1,col2) values(0,?)
    """
    cursor.execute(prepare,(True,))
    cursor.execute(prepare,(False,))
    cursor.execute(prepare,(None,))
    cursor.commit()

    select = "select * from tab_boolean"
    cursor.execute(select)
    result = cursor.fetchall()
    for row in result :
        print("字段 1的类型serail   ,值为：{}" . format(row[0]))
        print("字段 2的类型boolean  ,值为：{}" . format(row[1]))
```

### 扩展类型LIST  
LIST类型：list(TYPE not null)  
参考代码：test_list_type.py  
```python
    create = """
    create table tab_list(
        col1 serial not null,
        col2 LIST(varchar(20) not null)
    )
    """
    cursor.execute(create)
    cursor.commit()

    prepare = """
    insert into tab_list(col1,col2) values(0,?)
    """
    col2_list = "LIST{'aaaa','bbbb','cccc'}"
    cursor.execute(prepare, col2_list)
    cursor.commit()

    select = "select * from tab_list"
    cursor.execute(select)
    data = cursor.fetchall()
    for result in data:
        print("字段 1的类型serail   ,值为：{}" . format(result[0]))
        print("字段 2的类型list     ,值为：{}" . format(result[1]))
```

### JSON和BSON类型  
JSON类型：以字符形式存储  
BSON类型：可以以字符形式或者二进制形式存储  
参考代码：test_json_bson_type.py  
```python
    create = """
    create table tab_json_bson(
        col1 serial not null,
        col2 bson,
        col3 json
    )
    """
    cursor.execute(create)
    cursor.commit()

    prepare = "insert into tab_json_bson(col1,col2,col3) values(0,?,?)"
    col2_bson = "bson类型输入"
    col3_json = "json类型输入"
    cursor.execute(prepare,[col2_bson,col3_json])
    cursor.commit()

    select = "select col1,col2,col3 from tab_json_bson"
    cursor.execute(select)
    while True :
        row = cursor.fetchone()
        if not row:
            break
        print("字段1的值为：", row.col1)
        print("字段2的值为：", row.col2)
        print("字段3的值为：", row.col3)
```
### 大对象类型  
包含：  
text和byte  
两种类型均使用bytes来处理  
参考代码：test_byte_text_type.py  
```python
    create = """
    create table tab_lob(
        col1 serial not null,
        col2 byte,
        col3 text
    )
    """
    cursor.execute(create)
    cursor.commit()

    prepare = "insert into tab_lob(col1,col2,col3) values(0,?,?)"
    col2_byte = bytes('byte类型输入', encoding='UTF-8')
    col3_text = bytes('text类型输入', encoding='UTF-8')
    cursor.execute(prepare,[col2_byte,col3_text])
    cursor.commit()

    select = "select col1,col2,col3 from tab_lob"
    cursor.execute(select)
    while True :
        row = cursor.fetchone()
        if not row:
            break
        print("字段1的值为：", row.col1)
        print("字段2的值为：", row.col2.decode())
        print("字段3的值为：", row.col3)
```
### 智能大对象类型  
包含： 
blob和clob  
两种类型均只可以查询，只能使用函数操作插入  
clob类型似乎结果集有多余的数据？  
参考代码：test_blob_clob_type.py  
```python
    create = """
    create table tab_lob(
        col1 serial not null,
        col2 blob,
        col3 clob
    )
    """
    cursor.execute(create)
    cursor.commit()

    blob_str  = 'blob类型输入，最大支持4TB'
    blob_file = open('blob_file.txt', 'w',encoding='utf-8')
    blob_file.write(blob_str)
    blob_file.close()

    clob_str  = 'clob类型输入，最大支持4TB'
    clob_file = open('clob_file.txt', 'w',encoding='utf-8')
    clob_file.write(clob_str)
    clob_file.close()

    prepare = "insert into tab_lob(col1,col2,col3) values(0,filetoblob('blob_file.txt','client'),filetoclob('clob_file.txt','client'))"
    cursor.execute(prepare)
    cursor.commit()

    if(os.path.isfile('blob_file.txt')):
        os.remove('blob_file.txt')

    if(os.path.isfile('clob_file.txt')):
        os.remove('clob_file.txt')

    select = "select col1,col2,col3 from tab_lob"
    cursor.execute(select)
    while True :
        row = cursor.fetchone()
        if not row:
            break
        print("字段1的值为：", row.col1)
        print("字段2的值为：", row.col2.decode())
        print("字段3的值为：", row.col3)
```
**注意**  
Pyodbc使用的环境变量示例如下：  
```bash
export GBASEDBTDIR=/opt/gbase8s-odbc-driver
export CSDK_HOME=/opt/gbase8s-odbc-driver
export PATH=$GBASEDBTDIR/bin:$PATH
export LD_LIBRARY_PATH=$GBASEDBTDIR/lib:$GBASEDBTDIR/lib/cli:$GBASEDBTDIR/lib/esql:$LD_LIBRARY_PATH
export DB_LOCALE=zh_CN.utf8
export CLIENT_LOCALE=zh_CN.utf8
export GL_USEGLU=1
export ODBCINI=/opt/gbase8s-odbc-driver/etc/odbc.ini
```
参考代码：  
[test_pyodbc.tar.gz][1]
更多Pyodbc的信息参考：https://github.com/mkleehammer/pyodbc/wiki/  

  [1]: https://gbasedbt.com/usr/uploads/2023/03/2534642541.gz

Pyodbc对GBase 8s数据库的数据类型的支持

Pyodbc对GBase 8s数据库的数据类型的支持

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