Deleting row using composite key - google-cloud-platform

Question

I have the table 'column_defn' with the following schema. The keys are column_name,database_name and table_name
column_name STRING(130) NOT NULL
database_name STRING(150) NOT NULL
table_name STRING(130) NOT NULL
column_description STRING(1000) NOT NULL
I am trying to delete a row using the following REST request
{
"session":"xxxxxxxxx"
"singleUseTransaction": {
"readWrite": {}
},
"mutations": [
{
"delete": {
"table": "column_defn",
"keySet": {
"keys": [
[
{
"column_name": "testd"
},
{
"table_name": "test atbd"
},
{
"database_name": "ASDFDFS"
}
]
]
}
}
}
]
}
but I keep getting the following error. Any idea as to where is wrong in the above request
{
"error": {
"code": 400,
"message": "Invalid value for column database_name in table column_defn: Expected STRING.",
"status": "FAILED_PRECONDITION"
}
}
Update: The following request seems to be successful. At least it was returning the success code 200 and the commitTimestamp. However, the row didn't get deleted
{
"singleUseTransaction": {
"readWrite": {}
},
"mutations": [
{
"delete": {
"table": "column_defn",
"keySet": {
"keys": [
[
"testd",
"dsafd",
"test atbd"
]
]
}
}
}
]
}

Answer 1

keys should contain an array-of-arrays. In the outer array, there will be one entry for each row you are trying to delete. Each inner array will be the ordered list of key-values that define a single row (order matters). So in your example, you want:
"keys": [["testd","ASDFDFS","test atbd"]]
Note that the original question is inconsistent in the true ordering of the keys in the table. The above answer assumes the primary key is defined something like:
PRIMARY KEY(column_name,database_name,table_name)