摘要
ArcSDESQLExecute 类提供一种通过企业级地理数据库连接执行 SQL 语句的方法。
讨论
语法
ArcSDESQLExecute ({server}, {instance}, {database}, {user}, {password})| 参数 | 说明 | 数据类型 |
server | 安装数据库所在的服务器的名称或有效连接文件的名称。 | String |
instance | 端口号。 | String |
database | 数据库名称。 | String |
user | 用户名。 | String |
password | 用户名对应的密码。 | String |
属性
| 属性 | 说明 | 数据类型 |
| transactionAutoCommit (可读写) | 自动提交间隔。此属性可用于修改完指定数量的要素后强制执行阶段性提交。 | Integer |
方法概述
| 方法 | 说明 |
| commitTransaction () | 只有在调用 CommitTransaction 方法后，才提交 DML 语句。 |
| execute (sql_statement) | 通过 ArcSDE 连接向数据库发送 SQL 语句。如果在事务的外面运行 execute，则执行完 SQL DML（INSERT、UPDATE、DELETE . . .）语句后将自动发生提交。 |
| rollbackTransaction () | 将所有 DML 操作回滚到上一次提交。 |
| startTransaction () | 要控制向数据库提交更改的时间，请先调用 startTransaction 方法，然后再调用 execute。此方法用于启动事务，并且只有在调用 commitTransaction 方法后才提交 DML 语句。 |
方法
commitTransaction ()
execute (sql_statement)
| 参数 | 说明 | 数据类型 |
sql_statement | SQL 语句。 对于语句从表返回行的情况，execute 方法将返回一列列表；对于不返回行的语句，该方法将返回语句成功或失败的指示（True 表示成功；None 表示失败）。从单个行返回单个值的语句将以合适的类型（字符串、浮点型、浮点型）返回值。 | Variant |
rollbackTransaction ()
startTransaction ()
代码示例
查询每种犯罪类型的数量，然后返回含有犯罪类型和事件计数的列表。
import arcpy
# Use a connection file to create the connection
egdb = r'Database Connections\Connection to bedrock.sde'
egdb_conn = arcpy.ArcSDESQLExecute(egdb)
table_name = 'vtest.GDB.Crime'
field_name = 'CRIMETYPE'
sql = '''
SELECT {0}, COUNT({0}) AS f_count FROM {1}
GROUP BY {0}
ORDER BY f_count DESC
'''.format(field_name, table_name)
egdb_return = egdb_conn.execute(sql)
for i in egdb_return:
print('{}: {}'.format(*i))
执行一列 SQL 语句
import sys
import arcpy
try:
# Make data path relative
arcpy.env.workspace = sys.path[0]
# Two ways to create the object, which also creates the
# connection to the enterprise geodatabase.
# Using the first method, pass a set of strings containing
# the connection properties:
# <serverName>, <portNumber>, <version>, <userName>, <password>
# arcpy.ArcSDESQLExecute("gpserver3","5151","#","toolbox","toolbox")
# Using the second method pass the path to a valid connection file
egdb_conn = arcpy.ArcSDESQLExecute(r"data\Connection to GPSERVER3.sde")
# Get the SQL statements, separated by ; from a text string.
sql_statement = arcpy.GetParameterAsText(0)
sql_statement_list = sql_statement.split(";")
print("+++++++++++++++++++++++++++++++++++++++++++++\n")
# For each SQL statement passed in, execute it.
for sql in sql_statement_list:
print("Execute SQL Statement: {0}".format(sql))
try:
# Pass the SQL statement to the database.
egdb_return = egdb_conn.execute(sql)
except Exception as err:
print(err)
egdb_return = False
# If the return value is a list (a list of lists), display
# each list as a row from the table being queried.
if isinstance(egdb_return, list):
print("Number of rows returned by query: {0} rows".format(
len(egdb_return)))
for row in egdb_return:
print(row)
print("+++++++++++++++++++++++++++++++++++++++++++++\n")
else:
# If the return value was not a list, the statement was
# most likely a DDL statement. Check its status.
if egdb_return == True:
print("SQL statement: {0} ran successfully.".format(sql))
else:
print("SQL statement: {0} FAILED.".format(sql))
print("+++++++++++++++++++++++++++++++++++++++++++++\n")
except Exception as err:
print(err)
使用事务进行条件更新
# WARNING - DO NOT USE ON VERSIONED TABLES OR FEATURE CLASSES.
# DO NOT USE ON ANY enterprise geodatabase SYSTEM TABLES.
# DOING SO MAY RESULT IN DATA CORRUPTION.
import sys
import arcpy
try:
# Make data path relative (not relevant unless data is moved
# here and paths modified)
arcpy.env.workspace = sys.path[0]
# Column name:value that should be in the record.
sql_values = {"STREET_NAM": "'EUREKA'"}
# Value that is incorrect if found in the above column.
bad_val = "'EREKA'"
#List of tables to look in for the bad value.
tables = ["streetaddresses_blkA", "streetaddresses_blkB",
"streetaddresses_blkC"]
# Two ways to create the object, which also creates the connection
# to the enterprise geodatabase.
# Using the first method, pass a set of strings containing the
# connection properties:
# <serverName>, <portNumber>, <version>, <userName>, <password>
egdb_conn = arcpy.ArcSDESQLExecute("gpserver3", "5151", "#",
"toolbox", "toolbox")
# Using the second method pass the path to a valid enterprise geodatabase connection file
# arcpy.ArcSDESQLExecute("data\Connection to GPSERVER3.sde")
for tbl in tables:
print("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++")
for col, val in list(sql_values.items()):
print("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++")
# Check for the incorrect value in the column for the
# specific rows. If the table contains the incorrect value,
# correct it using the update SQL statement.
print("Analyzing table {0} for bad data: "
"Column:{1} Value: {2}".format(tbl, col, bad_val))
try:
sql = "select OBJECTID,{0} from {1} where {0} = {2}".format(
col, tbl, bad_val)
print("Attempt to execute SQL Statement: {0}".format(sql))
egdb_return = egdb_conn.execute(sql)
except Exception as err:
print(err)
egdb_return = False
if isinstance(egdb_return, list):
if len(egdb_return) > 0:
print("Identified {0} rows with incorrect data. Starting "
"transaction for update.".format(len(egdb_return)))
# Start the transaction
egdb_conn.startTransaction()
print("Transaction started...")
# Perform the update
try:
sql = "update {0} set {1}={2} where {1} = {3}".format(
tbl, col, val, bad_val)
print("Changing bad value: {0} to the good value: "
"{1} using update statement:\n {2}".format(
bad_val, val, sql))
egdb_return = egdb_conn.execute(sql)
except Exception as err:
print(err)
egdb_return = False
# If the update completed successfully, commit the
# changes. If not, rollback.
if egdb_return == True:
print("Update statement: \n"
"{0} ran successfully.".format(sql))
# Commit the changes
egdb_conn.commitTransaction()
print("Committed Transaction")
# List the changes.
try:
print("Displaying updated rows for "
"visual inspection.")
sql = "select OBJECTID" + \
",{0} from {1} where {0} = {2}".format(
col, tbl, val)
print("Executing SQL Statement: \n{0}".format(sql))
egdb_return = egdb_conn.execute(sql)
except Exception as err:
print(err)
egdb_return = False
if isinstance(egdb_return, list):
print("{0} rows".format(len(egdb_return)))
for row in egdb_return:
print(row)
print("++++++++++++++++++++++++++++++++++++++++\n")
else:
if egdb_return == True:
print("SQL statement: \n{0}\n"
"ran successfully.".format(sql))
else:
print("SQL statement: \n{0}\n"
"FAILED.".format(sql))
print("++++++++++++++++++++++++++++++++++++++++\n")
print("++++++++++++++++++++++++++++++++++++++++\n")
else:
print("SQL statement: \n{0}\nFAILED. "
"Rolling back all changes.".format(sql))
# Rollback changes
egdb_conn.rollbackTransaction()
print("Rolled back any changes.")
print("++++++++++++++++++++++++++++++++++++++++\n")
else:
print "No records required updating."
# Disconnect and exit
del egdb_conn
print("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++")
except Exception as err:
print(err)